Since the time of the discovery of the fission of the nucleus, when Hahn and Strassmann first detected the products of nuclear fission in 1939 in uranium irradiated by neutrons, over two decades have passed. In the work accom plished since that time, research has been greatly expanded on fission products and has been extended to many nuclides formed in the fission of various nu clei induced by neutrons, gamma rays, charged particles, and in spontaneous fission. Amassing of experimental results is an important task not only for nu clear engineering but also for an understanding of the fission process itself, for bringing into existence a finished theory on the unique and intriguing physi cal phenomenon which plays such a decisive role in the practical utilization of nuclear energy. In this reference manual, an attempt is made to collect and generalize upon the results of experimental research work over the period spanning 1939 to 1962, on yields of fission products and on the mass distribution of fission fragments. Various instances of the fission of nuclei induced by neutrons, gamma rays, charged particles, and spontaneous fission of nuclei are discussed."