diff --git a/src/lib/meta/function.hpp b/src/lib/meta/function.hpp
index 4f5617601..13ae3d097 100644
--- a/src/lib/meta/function.hpp
+++ b/src/lib/meta/function.hpp
@@ -128,6 +128,7 @@ namespace meta{
       using Args = Types<ARGS...>;
       using Sig  = RET(ARGS...);
       using Functor = std::function<Sig>;
+      enum { ARITY = sizeof...(ARGS) };
     };
   
   /** Specialisation to strip `noexcept` from the signature */
diff --git a/src/lib/thread.hpp b/src/lib/thread.hpp
index 70e4ee91f..d66b1a2d6 100644
--- a/src/lib/thread.hpp
+++ b/src/lib/thread.hpp
@@ -124,6 +124,7 @@
 #include "lib/nocopy.hpp"
 #include "include/logging.h"
 #include "lib/meta/trait.hpp"
+#include "lib/meta/function.hpp"
 #include "lib/format-util.hpp"
 #include "lib/result.hpp"
 
@@ -146,6 +147,7 @@ namespace lib {
   namespace thread {// Thread-wrapper base implementation...
     
     using lib::meta::typeSymbol;
+    using lib::meta::_Fun;
     using std::function;
     using std::forward;
     using std::move;
@@ -302,24 +304,18 @@ namespace lib {
         using BasePol = PolicyLaunchOnly<BAS>;
         using BasePol::BasePol;
         
-        using Hook = function<void(TAR&)>;
+        using Self = PolicyLifecycleHook;
+        using Hook = function<void(Self&)>;
         
         Hook hook_beginThread{};
         Hook hook_afterThread{};
         Hook hook_looseThread{};
         
-        TAR&
-        castInstance()
-          {
-            return static_cast<TAR*>(
-                   static_cast<void*> (this));
-          }
-        
         void
         handle_begin_thread()
           {
             if (hook_beginThread)
-              hook_beginThread (castInstance());
+              hook_beginThread (*this);
             else
               BasePol::handle_begin_thread();
           }
@@ -328,16 +324,16 @@ namespace lib {
         handle_after_thread()
           {
             if (hook_afterThread)
-              hook_afterThread (castInstance());
-            else
-              BasePol::handle_after_thread();
+              hook_afterThread (*this);
+            if (BAS::isLive())  // Note: ensure thread is detached at end
+              BAS::threadImpl_.detach();
           }
         
         void
         handle_loose_thread()
           {
             if (hook_looseThread)
-              hook_looseThread (castInstance());
+              hook_looseThread (*this);
             else
               BasePol::handle_loose_thread();
           }
@@ -486,7 +482,7 @@ namespace lib {
             
             template<typename HOOK>
             Launch&&
-            atEnd (HOOK&& hook)
+            atExit (HOOK&& hook)
               {
                 return addHook (&Policy::hook_afterThread, forward<HOOK> (hook));
               }
@@ -503,11 +499,29 @@ namespace lib {
             Launch&&
             addHook (FUN Policy::*storedHook, HOOK&& hook)
               {
-                return addLayer ([storedHook, hook = forward<HOOK>(hook)]
+                static_assert(1 == _Fun<FUN>::ARITY);
+                static_assert(1 >= _Fun<HOOK>::ARITY);
+                using Arg = typename _Fun<FUN>::Args::List::Head;
+                FUN adapted;
+                if constexpr (0 == _Fun<HOOK>::ARITY)
+                  {
+                    adapted = [hook = forward<HOOK>(hook)](Arg){ hook(); };
+                  }
+                else
+                  {
+                    using Target = typename _Fun<HOOK>::Args::List::Head;
+                    adapted = [hook = forward<HOOK>(hook)]
+                              (Arg& threadWrapper)
+                                {
+                                  ThreadLifecycle& base = static_cast<ThreadLifecycle&> (threadWrapper);
+                                  Target&        target = static_cast<Target&> (base);
+                                  hook (target);
+                                };
+                  }
+                return addLayer ([storedHook, hook = move(adapted)]
                                  (ThreadLifecycle& wrapper)
                                     {
-                                      wrapper.*storedHook = move (hook);
-                                      chain (wrapper);
+                                      wrapper.*storedHook = move(hook);
                                     });
               }
             
@@ -665,6 +679,29 @@ namespace lib {
   
   
   
+  /************************************************************************//**
+   * Extended variant of the [standard case](\ref Thread), allowing to install
+   * callbacks (hook functions) to be invoked during thread lifecycle:
+   * - `atStart` : invoked as first user code in the new thread
+   * - `atExit` : invoked as the last user code prior to detaching and thread end
+   * - `onOrphan` : invoked from the thread-wrapper destructor, when the actual
+   *   thread is detected as still running (according to the thread handle)
+   * By default, these callbacks are empty; custom callbacks can be installed
+   * through the ThreadLifecycle::Launch configuration builder using the
+   * corresponding builder functions (e.g. `.atExit(λ)`). The passed functor
+   * can either take no argument, or a single argument with a reference to
+   * some `*this` subtype, which must be reachable by static downcast from
+   * the ThreadLifecycle base type.
+   */
+  class ThreadHookable
+    : public thread::ThreadLifecycle<thread::PolicyLifecycleHook>
+    {
+    public:
+      using ThreadLifecycle::ThreadLifecycle;
+    };
+  
+  
+  
   /************************************************************************//**
    * Special configuration for a »fire-and-forget«-Thread.
    * @internal this class is meant for subclassing. Start with #launchDetached()
diff --git a/tests/library/thread-wrapper-lifecycle-test.cpp b/tests/library/thread-wrapper-lifecycle-test.cpp
index 6e16b5be5..b6be52b3e 100644
--- a/tests/library/thread-wrapper-lifecycle-test.cpp
+++ b/tests/library/thread-wrapper-lifecycle-test.cpp
@@ -40,7 +40,7 @@ using lib::explore;
 using std::atomic_uint;
 using std::this_thread::yield;
 using std::this_thread::sleep_for;
-using std::chrono::microseconds;
+using namespace std::chrono_literals;
 using std::chrono::system_clock;
 
 
@@ -69,7 +69,8 @@ namespace test{
         run (Arg)
           {
             defaultWrapperLifecycle();
-            verifyExplicitLifecycleState();
+            verifyThreadLifecycleHooks();
+            demonstrateExplicitThreadLifecycle();
           }
         
         
@@ -90,14 +91,6 @@ namespace test{
             double offset = Dur{threadStart - afterCtor}.count();
 SHOW_EXPR(offset)
             CHECK (offset > 0);
-
-            Thread murks{Thread::Launch([&](uint scope)
-                                           {
-                                             cout << "Hello nested world "<<rand()%scope <<endl;
-                                           }
-                                       , 47)
-                                .threadID("haha")};
-            UNIMPLEMENTED ("demonstrate state change");
           }
         
         
@@ -106,8 +99,35 @@ SHOW_EXPR(offset)
          *       the thread's lifecycle state.
          */
         void
-        verifyExplicitLifecycleState()
+        verifyThreadLifecycleHooks()
           {
+            atomic_uint stage{0};
+            ThreadHookable thread{ThreadHookable::Launch([]{ sleep_for (5ms); })
+                                                .threadID("hooked thread")
+                                                .atStart([&]{ stage = 1; })
+                                                .atExit ([&]{ stage = 2; })};
+            
+            CHECK (thread);
+            CHECK (0 == stage);
+            
+            sleep_for (1ms);
+            CHECK (thread);
+            CHECK (1 == stage);
+            
+            while (thread) yield();
+            CHECK (not thread);
+            CHECK (2 == stage);
+          }
+        
+        
+        /**
+         * @test verify a special setup to start a thread explicitly and to track
+         *       the thread's lifecycle state.
+         */
+        void
+        demonstrateExplicitThreadLifecycle()
+          {
+            UNIMPLEMENTED ("demonstrate state change");
               struct TestThread
                 : Thread
                 {
@@ -119,39 +139,10 @@ SHOW_EXPR(offset)
                   doIt (uint a, uint b) ///< the actual operation running in a separate thread
                     {
                       uint sum = a + b;
-                      sleep_for (microseconds{sum});  // Note: explicit random delay before local store
+//                      sleep_for (microseconds{sum});  // Note: explicit random delay before local store
                       local = sum;
                     }
                 };
-            
-            // prepare Storage for these objects (not created yet)
-            lib::ScopedCollection<TestThread> threads{NUM_THREADS};
-            
-            size_t checkSum = 0;
-            size_t globalSum = 0;
-            auto launchThreads = [&]
-                                  {
-                                    for (uint i=1; i<=NUM_THREADS; ++i)
-                                      {
-                                        uint x = rand() % 1000;
-                                        globalSum += (i + x);
-                                        threads.emplace (&TestThread::doIt, i, x);
-                                      }                            // Note: bind to member function, copying arguments
-                                    
-                                    while (explore(threads).has_any())
-                                      yield();                  // wait for all threads to have detached
-                                    
-                                    for (auto& t : threads)
-                                      {
-                                        CHECK (0 < t.local);
-                                        checkSum += t.local;
-                                      }
-                                  };
-            
-            double runTime = benchmarkTime (launchThreads, REPETITIONS);
-            
-            CHECK (checkSum == globalSum);           // sum of precomputed random numbers matches sum from threads
-            CHECK (runTime < NUM_THREADS * 1000/2);  // random sleep time should be > 500ms on average
           }
       };
     
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index 056657e52..6d5ed6361 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -65242,7 +65242,7 @@
 <icon BUILTIN="forward"/>
 </node>
 </node>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1696898745626" ID="ID_1404625774" MODIFIED="1696898766166" TEXT="mu&#xdf; einen gewaltsamen Upcast machen">
+<node COLOR="#435e98" CREATED="1696898745626" ID="ID_1404625774" MODIFIED="1696958131450" TEXT="mu&#xdf; einen gewaltsamen Upcast machen">
 <icon BUILTIN="messagebox_warning"/>
 <node CREATED="1696898767838" ID="ID_982197270" MODIFIED="1696898773034" TEXT="und zwar &#xfc;ber void*"/>
 <node CREATED="1696898773597" ID="ID_1027296232" MODIFIED="1696898787176" TEXT="weil wir einmal protected-Inheritance verwenden"/>
@@ -65262,6 +65262,10 @@
 </html></richcontent>
 <icon BUILTIN="clanbomber"/>
 </node>
+<node COLOR="#435e98" CREATED="1696958144365" ID="ID_1650867169" MODIFIED="1696958397510" TEXT="stattdessen: sichere L&#xf6;sung &#xfc;ber den Launch-config builder">
+<arrowlink COLOR="#3bacb8" DESTINATION="ID_1240123723" ENDARROW="Default" ENDINCLINATION="561;0;" ID="Arrow_ID_187329351" STARTARROW="None" STARTINCLINATION="386;18;"/>
+<icon BUILTIN="idea"/>
+</node>
 </node>
 <node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1696532299942" ID="ID_596357210" MODIFIED="1696898738780" TEXT="die jeweilige Front-End-Klasse nur in der Factory definieren">
 <icon BUILTIN="yes"/>
@@ -65386,7 +65390,8 @@
 <icon BUILTIN="stop-sign"/>
 </node>
 </node>
-<node CREATED="1696934198943" ID="ID_737180308" MODIFIED="1696934210349" TEXT="besser: funktionale Erweiterungspunkte">
+<node COLOR="#435e98" CREATED="1696934198943" ID="ID_737180308" MODIFIED="1696958409322" TEXT="besser: funktionale Erweiterungspunkte">
+<icon BUILTIN="yes"/>
 <node CREATED="1696934212695" ID="ID_1626568717" MODIFIED="1696934238138" TEXT="diese werden als std::function gespeichert"/>
 <node CREATED="1696934261703" ID="ID_266607477" MODIFIED="1696934280168" TEXT="und aus entsprechenden Policy-hooks heraus aufgerufen"/>
 <node CREATED="1696934280923" ID="ID_787857879" MODIFIED="1696934285592" TEXT="Hooks">
@@ -65395,7 +65400,7 @@
 <linktarget COLOR="#fdfcc6" DESTINATION="ID_1004228427" ENDARROW="Default" ENDINCLINATION="-114;10;" ID="Arrow_ID_936715522" SOURCE="ID_1539716722" STARTARROW="None" STARTINCLINATION="116;8;"/>
 </node>
 <node CREATED="1696529836760" ID="ID_1153306127" MODIFIED="1696934476853" TEXT="zus&#xe4;tzlich: &#x27ff; handle_loose_thread">
-<linktarget COLOR="#fdfcc6" DESTINATION="ID_1153306127" ENDARROW="Default" ENDINCLINATION="-114;10;" ID="Arrow_ID_880044186" SOURCE="ID_1868637331" STARTARROW="None" STARTINCLINATION="263;12;"/>
+<linktarget COLOR="#fdfcc6" DESTINATION="ID_1153306127" ENDARROW="Default" ENDINCLINATION="-341;27;" ID="Arrow_ID_880044186" SOURCE="ID_1868637331" STARTARROW="None" STARTINCLINATION="263;12;"/>
 <node CREATED="1696933886929" HGAP="25" ID="ID_796423082" MODIFIED="1696933932976" TEXT="(wird aufgerufen aus dem Destruktor &#x2014; falls der Thread noch l&#xe4;uft)" VSHIFT="7">
 <font NAME="SansSerif" SIZE="11"/>
 <icon BUILTIN="info"/>
@@ -65403,6 +65408,37 @@
 </node>
 </node>
 </node>
+<node COLOR="#338800" CREATED="1696958202741" ID="ID_1577864867" MODIFIED="1696958412378" TEXT="diese bereits im Launch-config-builder adaptieren">
+<icon BUILTIN="button_ok"/>
+<node COLOR="#338800" CREATED="1696958220491" ID="ID_1240123723" MODIFIED="1696958388855" TEXT="das l&#xf6;st das Problem mit dem downcast auf einen Subklassen-Typ">
+<linktarget COLOR="#3bacb8" DESTINATION="ID_1240123723" ENDARROW="Default" ENDINCLINATION="561;0;" ID="Arrow_ID_187329351" SOURCE="ID_1650867169" STARTARROW="None" STARTINCLINATION="386;18;"/>
+<icon BUILTIN="button_ok"/>
+</node>
+<node CREATED="1696958235467" ID="ID_1922263135" MODIFIED="1696958334910">
+<richcontent TYPE="NODE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      <i>ganz elegant </i>erst mal auf TheadLifecycle downcasten
+    </p>
+  </body>
+</html></richcontent>
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      was &#8222;rein zuf&#228;llig&#8220; hier in diesem nested scope in ThreadLifecycle erlaubt und auch sicher ist, denn hier haben wir noch Zugriff auf die protected geerbten Policy-Klassen...
+    </p>
+  </body>
+</html></richcontent>
+</node>
+<node CREATED="1696958336516" ID="ID_564028687" MODIFIED="1696958350950" TEXT="im zweiten Schritt von dort dann auf einen beliebigen Subtyp"/>
+<node CREATED="1696958351770" ID="ID_174542726" MODIFIED="1696958368388" TEXT="den konkret vom gegebenen &#x3bb; erwarteten Argument-Typ verwenden"/>
+</node>
 </node>
 <node CREATED="1696532838782" ID="ID_46766207" MODIFIED="1696532858447" TEXT="der Konflikt im Lebensdauer-Thema ist damit beigelegt">
 <node CREATED="1696532860011" ID="ID_132397075" MODIFIED="1696532867737" TEXT="bisher hatten wir hier einen Zielkonflikt"/>
@@ -66022,9 +66058,12 @@
 <node CREATED="1696538612261" ID="ID_661367597" MODIFIED="1696538614839" TEXT="f&#xfc;r Variante-2">
 <node CREATED="1696933810166" ID="ID_906750178" MODIFIED="1696933829261" TEXT="stelle Storage bereit als std::function"/>
 <node CREATED="1696529718984" ID="ID_1868637331" MODIFIED="1696934476853" TEXT="die schon definierten Hooks + zus&#xe4;tzlichen Erweiterungspunkt">
-<arrowlink COLOR="#fdfcc6" DESTINATION="ID_1153306127" ENDARROW="Default" ENDINCLINATION="-114;10;" ID="Arrow_ID_880044186" STARTARROW="None" STARTINCLINATION="263;12;"/>
+<arrowlink COLOR="#fdfcc6" DESTINATION="ID_1153306127" ENDARROW="Default" ENDINCLINATION="-341;27;" ID="Arrow_ID_880044186" STARTARROW="None" STARTINCLINATION="263;12;"/>
 <icon BUILTIN="idea"/>
 </node>
+<node COLOR="#338800" CREATED="1696958434135" ID="ID_1569167047" LINK="#ID_1240123723" MODIFIED="1696958461524" TEXT="Adaptierung auf beliebigen Subtyp automatisch">
+<icon BUILTIN="button_ok"/>
+</node>
 </node>
 </node>
 <node COLOR="#338800" CREATED="1696690988844" ID="ID_480585061" MODIFIED="1696861459249" TEXT="das Race-Problem addressieren">