doc: Manager pattern

some more thoughts

Author: dancergraham

chapter14_leftover/readme.md

@@ -7,5 +7,9 @@ mediator pattern which handles interaction between related objects, the
 manager pattern has the role of managing multiple identical or related objects.
 
 For example in the Python standard library the [`Manager` object](https://docs.python.org/3/library/multiprocessing.html#multiprocessing.Manager)
-in the `multiprocessing` library manages shared objects between child
-processes.
+in the `multiprocessing` library manages shared objects and child processes.
+It keeps track of the running processes, shared objects and the available methods
+on those objects. Without a `Manager` object, multiple processes could try to access
+or modify shared objects at the same time with unpredictable results.  
+It uses the `Proxy` design pattern, providing a proxy to the shared objects, to help 
+achieve this, passing messages and data across process boundaries.