This annual report details progress in basic research in thermoacoustic heat transport made during the period October 1, 1989 through September 30, 1990. Four projects are discussed. The first project involves measurements of thermoacoustic phenomena using thermoacoustic couples (TACs). The purpose of the second project is to examine means of visualizing thermoacoustic processes. The third project is an investigation of heat driven prime movers. The fourth project considers the performance of thermoacoustic heat engines that operate with an acoustic sound field that is not a perfect standing wave. A publications, patents, presentations, and honors report is also included.