In Lebor Ogaim ("The Book of Ogams"), also known as the Ogam Tract, is an Old Irish treatise on the ogham alphabet. It is preserved in R.I.A. MS 23 P 12 308–314 (AD 1390), T.C.D. H.3.18, 26.1–35.28 (AD 1511) and National Library of Ireland MS G53 1–22 (17th century), and fragments in British Library Add. 4783. It does not bear a title in the manuscripts, but it is mentioned in the Auraicept na n-Éces (2813f.) as amal isber in leapar ogaim, whence the commonly used title. The Ogham Tract is independent of the Auraicept, and is our main source for the Bríatharogaim.