From the introduction to the document:
Chronomancer is a 96-page booklet for TSR's AD&D(R) game that presents, for the first time ever, a school of wizard's magic that allows player characters to travel through Time itself, in almost any campaign world.
This article is an updated and expanded excerpt from the Chronomancer accessory. It describes how these rules for time travel can be merged with any of the major official campaigns for the AD&D game. Many game designers, editors, and creative directors have added their comments to make this material more complete and interesting; to them I give my eternal thanks.