And, according to Atkinson's web page, a second edition is being considered. With only one PHP book available, such popularity might be attributed to the subject rather than the quality of the book. Atkinson's writing is uncommonly concise and comprehensive. Atkinson begins sensibly with an introduction to the language, detailing its advantages over the competition. With something as intentionally transparent as a web scripting language, such discussion is vital.
Surfers have little chance of knowing which sites employ any web scripting language.
For instance, the popular software site for Linux, freshmeat.net, uses PHP exclusively, although users cannot detect it viewing the opening page. PHP's introduction and language basics comprise the first of four sections in the book. The introduction is quite rudimentary, suitable for complete beginners to programming. Variable declaration and other important but introductory topics are discussed exclusively in the opening section. A section or two comparing PHP and Perl would have been nice.