Slashdot has published Book review - Extending and Embedding PHP book.
FTA, "...PHP is a widely-used general-purpose scripting language that is especially suited for Web development. The interpreter that executes programs written in the PHP programming language has been designed from the ground up to be easily embeddable (for instance into the Apache Web Server) and extendable. This extensibility is one of the reasons why PHP became the favourite "glue" of the Web: functionality from existing third-party libraries (database clients or image manipulation toolkits, for instance) can be made available through PHP with the ease of use you expect from a scripting language..."
Read the rest of Sebastian's review at Slashdot.