I've read in the past years the previous edition of this book (it covered 9i and 10g). Mr. Kyte is a fine technical writer, and he shows everything with real examples! This is a "must" for every Oracle DBA and Developer! Beyond a doubt, one of the best Oracle books ever written!
Hard to review this here in a few lines, but what I can say is that you really learn a lot about how the Oracle RDBMS works and how to use lots for your programming.
An extremely thorough guide to developing applications with the Oracle database, including information on the server architecture, data files, data types, indexes, encryption, and more.