The International Astronomical Union Colloquium on Stellar Rotation was held at the Ohio State University in Columbus, Ohio, U.S.A. from September 8th through 11 th, 1969. Forty-four scientists from Argentina, Belgium, Canada, England, Finland, East and West Germany, Italy, Israel, Japan, The Netherlands, and the United States attended and participated in the Colloquium. The present volume, which parallels the actual program closely, contains the papers presented at the Colloquium plus most of the discussion following those papers. The Colloquium was sponsored by the International...