[newbie] Difference between Desktop Environment/Window Manager

[Han2097]

What is the difference between a Window Manager, such as BlackBox, and a 
Desktop environment?  They seem to perform similar functions.  The 
differerence I've came up wtih is that the environments let one save things 
on the desktop, and provide for graphical customization of it, whereas there 
aren't many extras in Window Managers, although they seem to start and 
shutdown somewhat faster.  Is that the only thing?

Dan