This volume explains Powersoft's Foundation Class (PSF) library for Powerbuilder. It covers application development, tuning and maintenance, and running PowerBuilder on the Internet. It covers the latest 5.1 release. The CD-ROM contains templates and tools for building Internet applications. A class library is a collection of frequently used programs that software devlopers reuse when building applications. "C" was the first programming language to have class libraries, and every language and programming tool since has one.