HI Kenneth,
I had a look at ABAP OOP books available via SAP Press. As you said they are all quite old - approx. around year 2007-2009. The newest are from 2011:
Next Generation ABAP Development (2nd Edition) - 2011 but not exactly ABAP Object book
The Official ABAP Reference (3rd Edition) - kind of general ABAP book
but again they are not covering the latest new things. Therefore I'd would suggest you to follow TechEd sessions where usually all new topic are presented. e.g. some link:
https://www.sapteched.com/sessions.htm
@Venkat: ABAP in 21 days is very old book - in 2001 when I started to work with SAP it was already there. Kenneth is specifically looking for ABAP Object related book.
regards,
m./