http://www.cs.williams.edu/~kim/FOOPL/Bruce.1.2.gif

''Foundations of Object-Oriented Programming Languages'' by Kim B. Bruce (ISBN 0-262-02523-X).  


Good book on TypeTheory as applied to OO-languages.  A bit simpler to digest than TypesAndProgrammingLanguages, though not as comprehensive of a treatment on the subject.


----

CategoryBook TypeTheory