Here on the ruby-talk list we've all gone through the pickaxe book and I've gone through
most of the first Ruby Way.  So you're not necessarily asking the Ruby-Nuby group you
might be pointing your book at...

What I wanted and did not have was a good set of exercises to train my mind into the new
mold.  Sort of "using the blah feature, figure out a way to code a whatever function" type
of question and about half of them should have answers.  I guess what I want is the Ruby
equivalent of the "C Puzzle Book" which is what made me an upper tier C programmer.  The C
Puzzle Book was very educational because for each topic it gave simple questions and
answers, and each succeeding question was just a little bit more sophisticated so by the
time you finished a chapter you were expert in that area.   

You could  add a series of exercises to the end of each chapter.  And put most of the
answers online where you would also have ads so you can make even more money.  Knuth has
exercises at the end of each of his chapters and his books are ever-popular classics.

There are core libraries that have stood the test of time and must be included.  What I
want in the library area though, is a set of rules and maybe programming exercises that
enable me to become a top-tier writer of Ruby libraries.  What, for example, is the Ruby
answer to the versioning questions?  (You know, when the new version of the base class has
a new method with the same name as a method in a derived class I'm already using...)

Warren Seltzer