The purpose of the article is to present further information about Avicenna's work on Eastern philosophy, supplementing what was written in the author's Avicenna and the Aristotelian Tradition (Leiden, 1988), pp. 115-30. In view of the prevalent but unfounded notions among some students of Avicenna that the Eastern philosophy is mystical or illuminationist, an initial section traces the history of the development of these tendentious ideas first to Ibn T[dotu]ufayl and then to the followers of his interpretation in the West in the nineteenth and twentieth centuries. Further sections discuss the title of the book, list its contents insofar as they can be reconstructed from Avicenna's statements and the extant portions, and provide additional information about its manuscripts and transmission. The style of the work is then analyzed and compared with that of the šifā' in order to verify Avicenna's claim in the Preface to the latter work that the difference between the two was merely stylistic. A final section gives a table of concordance between the contents of the extant part on physics and the corresponding sections in the šifā', establishing the direct relationship and verbal congruity between the two works.