In other words, if you need a dry, succinct description of a particular concept or object, try the Reference Manual. Introductory topics, step-by-step instructions, and general discussions are available in the User Manual. Polygraph documentation also includes descriptions of standard workloads.
The entire Web Polygraph documentation is available for download as a single 650KB gzipped tar file.
Old Polygraph site at IRCache server contains information for versions prior to version 2.6.