Sixth Edition Basic Rules
XXVII Special Advance Edition
From the publisher:
[Ysgarth presents] classic roleplaying game rules, complete and detailed magic system, combat mechanics and alternative rules. Also includes substantial world background information.
First published in 1979, Ysgarth was the first classless fantasy roleplaying system, and the first system to offer a universal skill system, racial advantages, and a variety of other innovations later adapted by other games.