Abstract: In the spring of 1976, while searching through papers of the late G. N. Watson at Trinity College, Cambridge, George Andrews found a sheaf of 138 pages in the handwriting of Srinivasa Ramanujan, generally regarded as India’s greatest mathematician. In view of the fame of Ramanujan’s earlier notebooks, Andrews naturally called these papers Ramanujan’s “lost notebook.” This work, comprising about 650 results with no proofs, arises from the last year of Ramanujan’s life, and represents some of his deepest work. First, we provide a history of the lost notebook. Second, a general description of the contents of the lost notebook will be provided. Third, the remainder of the lecture will be devoted to a survey of some of the most interesting entries in the lost notebook. These include claims in q-series, theta functions, continued fractions, integrals, partitions, and other infinite series.