This Bulletin provides stability criteria for determiningthe structural adequacy against buckling of large diametercircular cylindrical members when subjected to axial load,bending, shear and external pressure acting independently orin combination. The cylinders may be unstiffened, longitudinallystiffened, ring stiffened or stiffened with both longitudinaland ring stiffeners. Research and development workleading to preparation and issue of the first and second editionsof this Bulletin is documented in References 1 through 6and the Commentary.