This book by Jason Gilmore and Robert Treat (published by Apress) is meant to be a comprehensive tutorial on the PHP language and PostgreSQL for beginners. Don't expect it to be a detailed book focused on using PHP with Postgres. It's like two books in one. 2/3 of the book is devoted to teaching PHP and it's well written and easy to understand with plenty of examples. It covers additional topics that other beginning books sometime don't cover such as networking, secure programming and web services although not necessarily in great detail, but I like that it seeds the topic into beginners' heads.
The latter 1/3 is devoted to Postgres and provides better coverage then other stand alone Postgres book and more accessible then the Postgres documentation. It discuss database topics, postgres setup and administration and is a good reference source.
I would recommend this book to those who want to learn either these technology especially those who are going to work with PHP since most likely you'll be needing a database beyond the SQLite solution that comes with PHP.
The only area that I wish would be improved is more details on web services on the PHP side and a discussion on database replication on the Postgres side.