A U.S.-Japan Seminar on recent advances in the understanding of structures and dynamics of the heliomagnetosphere, formally entitled “Recent Advances in the Understanding of Structure and Dynamics of the Heliomagnetosphere During the Current Maximum and Declining Phase of Solar Activity,” was held on November 5–9 , 1984, in Kyoto, Japan. There were 46 papers presented in seven sessions. Among this total, 22 papers can be classified as observational and analysis papers, 18 may be considered theory and modeling papers, and 6 were papers dealing with programing methods. A total of 60 scientists attended this seminar: 19 from the United States, one from the Netherlands, one from India, and the rest from Japan. In addition, three graduate students were in attendance. This account of the seminar, which was sponsored by the National Science Foundation and Japan Society for the Promotion of Science, will be organized according to four topical categories: large-scale structures, mass ejection and heliospheric dynamics, particle acceleration and cosmic rays, and solar radio emission.