PET is a library of PHP classes for use with the Entrez API. They give easy access to the NCBI databases, including PubMed, PubMed Central, OMIM, and the various *omics databases. The library is currently primitive, but under active development. Because PHP is one of the easiest languages to learn and is in very widespread use, it is hoped that PET may give those without extensive programming skills the ability to quickly produce useful services.\nPET services\n\nFive publically available services currently run with PET:\n\nAssEd:\n The semi-automatic assistant editor: a device for comparing multiple pubmed search results in order to find authors in common between them. Use when you are searching for an author who has published on two or more subjects, but where it is not important whether the two subjects occur in the same paper.\nOAFF:\n The open-access friend finder: a device for searching PubMed Central and returning a list of the most-published authors on a particular topic (or location). Use when searching for those authors in a field who most friendly toward open-access publishing.\nTiPS:\n Trends in Publishing Science: a device for creating graphs to show monthly trends in PubMed depositions for a particular topic, journal, location, etc.\nPubMed Cloud:\n A toy which runs a PubMed search and then generates the HTML for a word cloud from all of the abstracts in that search.\nAuthor Profile:\n Displays somebody's PubMed record, but with useful statistics and trends. You can use it from the search box on the left, or from the links in AssEd and OAFF results.