In so far as a book may be pronounced useful which has ministered to a continual demand, the utility of the Abhidhammattha-sangaha ranks very high among the world's historical documents. For probably eight centuries it has served as a primer of psychology and philosophy in Ceylon and Burma, and a whole literature of exegesis has grown up around it. In at least three Pali books of history and bibliography, of uncertain, if not very early date, but based on older works now lost, the manual is ascribed to a teacher named Anuruddha. According to the Burmese tradition, Anuruddha was a Thera (elder) of Ceylon, and wrote the Compendium at the Sinhalese Vihara, founded by Somadevi, Queen of King Vattagamani (88-76 B.C.), and the Minister Mula, at Polonaruwa. Wherever or whenever written, the Compendium is, in Burmese bibliography, classed under a group of classical summaries, or compendia, entitled Let-than, or Little-finger Manuals, nine in number, and having, most of them, an exegetical literature belonging to each work.