The general improvement of the design of reinforced concrete columns has been a priority in the work of the Reinforced Concrete Research Council. In 1960 a series of studies was proposed to define the behavior of long reinforced concrete columns in frames. The studies are included in this publication. Studies on limit design aspects of column and frame stability were proposed in 1967. Findings from these studies, which are also included in this book, resulted in important changes in the slenderness provisions for reinforced concrete columns adopted in the 1983 ACI building code.