Andrew,
  One good book specific to CSET++ 2.1 User Interface Library is 
"OS/2 C++ Class Library: Power GUI programming with C Set++",
by Kevin leong, at al. ISBN 0-472-0195-2.
  This book covers IBM User Interface Class Library from a 
programming guide point of view, and may used as reference 
to a certain degree. 
  This book assumed that you have a good knowledge of the 
C++ programming language. 
  I hope this is helpful for you.
Cheers!
YounChin

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