Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In mathematics, a Rota Baxter algebra is an algebra, usually over a field k, together with a particular k-linear map R which satisfies the weight- Rota Baxter identity. It appeared first in the work of the American mathematician Glen Baxter in the realm of probability theory. Baxter''s work was further explored from different angles by Gian-Carlo Rota, Pierre Cartier, and Frederic V. Atkinson, among others. Baxter''s derivation of this identity that later bore his name emanated from some of the fundamental results of the famous probabilist Frank Spitzer in random walk theory. The Spitzer identity appeared is named after the American mathematician Frank Spitzer. It is regarded as a remarkable stepping stone in the theory of sums of independent random variables in fluctuation theory of probability. It can naturally be understood in terms of Rota Baxter operators.