The writer proposed to make an investigation of overseas in situ gasification work a main objective of a study leave tour in 1976. The extensive travel involved was made possible by support offered by the Energy Commission of Western Australia, the Queensland Electricity Commission, and the C.S.R. Co., to supplement the University travel grant. This report is produced with sincere appreciation of the support offered. The three major research groups in the USA in this field (Laramie Energy Research Center, Laurence Livermore Laboratories and Morgantown Energy Research Center) were visited.