Arahant Upatissa (1st century CE – 2nd century CE) was a Sri Lankan TheravadaBuddhistmonk and the author of ''The Path to Freedom'', or ''Vimuttimagga'', which serves as a Buddhist meditation manual, broadly considered a great and important work. It is similar to the Path of Purification, or ''Visuddhimagga'' by Buddhaghosa, but less analytical and more practical in its treatment of the traditional meditation objects. Both are commentaries, not from the Pali Canon, but very relevant to it, especially to the section of the Pali Canon called the Abhidhamma which contains the philosophical treatises of the Buddha.
Provided by Wikipedia