a comprehensive Tkinter document?

[William Gill]

I know a major problem I am having is that I am finding lots of Tkinter 
information in 'fragments' of various , sometimes conflicting vintages. 
  For example the python reference I was using didn't show the '%%' as 
an escape sequence, I posted asking how to escape the '%' and after 
several helpful responses voila I found a more complete table of escape 
sequences.  Is there a comprehensive document or book that I can get 
that is relatively current?  I realize that updates and changes are 
dynamic, but I'm realizing that I am trying to use documents that look 
similar, only to find that one is several years old, or that another 
applies to an offshoot of Tkinter.  I'm not even sure Tkinter is the 
'preferred' gui anymore.  Any suggestions?

Bill