Web programming is usually not the first association that comes to mind when the term scientific programming is mentioned. For scientists, learning how to do so is a useful skill to develop and master. For the browser, client-side programming in JavaScript is probably the most familiar, since users need nothing special beyond a JavaScript-capable browser, which is already residing on their computer, and a text editor. Server-side programming is less frequently done, since the required server access is often restricted because of security concerns. If the server cannot be used, there is little motivation to do server-side programming.

If developers and users can access files and database information on a server, they can be freed from a number of spatial limitations on their work. PHP is one of the major programming languages for Web-based programming. Its syntax should be familiar to software writers who know JavaScript. It is portable across operating systems, easily integrated with database software such as MySQL, and can parse Extensible Markup Language (XML). There are ways in which PHP programs can be written in a standalone manner, independent of a physical client-server relationship. PHP generates Hypertext Markup Language (HTML) that embodies the response to a user action or request.

This book on PHP for scientists and engineers is a slim volume--only 141 pages, including the index at the end. PHP texts usually focus on e-commerce applications, such as shopping carts, document generation, and Web services. Applications in science and engineering that are analogous include logging data from field sites to a database system on a central server, and then acquiring and using this data after it is posted to the central resource. The full syntax of PHP can be used to process the data, either on the server or at the client side, in conjunction with JavaScript. PHP is not the language of choice for computationally bound problems. It is, however, quite suitable for handling problems in scientific or engineering data management and doing smaller scale calculations on this data.

The book does not purport to be a comprehensive guide to PHP; other reference materials need to be purchased and the language interpreter must be downloaded and installed. The book emphasizes those features that might be of immediate interest to a scientist or engineer, in these sections: the server-side environment, the structure of PHP scripts, file input/output (I/O), arrays (the most frequently used data structures in scientific programming), a synopsis of the language elements, and PHP from the command line. A set of programming exercises is provided at the end of the book. It teaches by example, using a theme and variation method: first, a general problem is posed; then, a first simple solution is developed and elaborated upon, to give more sophisticated results. Database programming is not treated at all. All I/O examples employ flat files.

Used alone, the book might not be very useful, since it does not treat acquisition and installation of the software, setting up a localhost for development, and some of the more general issues of using PHP for dynamic Web sites. The PHP Web site (http://www.php.net/) is the central archive of software and documentation. It would be useful for readers to have previous knowledge or practice with PHP, even if it is only with entirely irrelevant e-commerce applications. A novice coming to PHP without previous experience should get two books--a thick reference book on PHP and a copy of this splendid little introduction to scientific and engineering calculations using PHP.