An explanation of what killing a process really does

Tonight I want to introduce My Oracle Support article "Kill A Process - Not able to clear session" via note ID 1493261.1 which will give you the commands to kill the process, and terminate it, but what happens when that still does not disconnect the session?  The article has a fairly detailed explanation of what the interaction between the DB and target session is, which may surprise you as there are steps where commands are not given and instead are interpreted as asking!!