Anguttara Nikaya

The Anguttara Nikaya, the fourth division of the Sutta Pitaka, consists of several thousand suttas arranged in eleven books (nipatas) according to numerical content. For example, the first nipata — the Book of the Ones — contains suttas concerning a single topic; the second nipata — the Book of the Twos — contains suttas concerning pairs of things (e.g., a sutta about tranquillity and insight; another about the two people one can never adequately repay (one's parents); another about two kinds of happiness; etc.); the third nipata contains suttas concerning three things (e.g., a sutta on the three kinds of praiseworthy acts; another about three kinds of offense), and so on.