One of Mark Guzdial's students created a Squeak API swiki. It could be a
good start for a "Squeak in a Nutshell" book. I agree that it would be best
to have an online (semi)dynamic reference to reflect the most up-to-date
state of the system.

There are other beginnings, such as a number of Morphic references (most of
which cover essentially the same topics, though) that could be combined with
specific examples, downloadable code, to provide a fairly robust tutoring
system. One software company's products were praised for a comprehensive
help system with (most importantly) examples.

Finally, there is SqueakDoc, which covers a lot of areas, but may need some
editing for consistency (to be considered a "book").
http://minnow.cc.gatech.edu/squeakdoc

So maybe the SqueakDoc should become the starting/continuation point?

Bolot