This Manual is the 9th major update of the AISC Steel Construction Manual, which was first published in 1927. Replacing the 8th Edition Manual, the 9th Edition Manual contains several updates and revisions, including the new HP18 and HP16 series, updated connection tables based on increased bolt shear strength values, revised single-plate and extended single-plate connection design procedures, enhanced prying action procedure, and a revised bracket plate design procedure.