This document list the main parameters of the Advanced Photon Source injector synchrtron known as the booster. The contents and style are based on the ANL/APS/TB-26 document [1] compiled by H. Bizek [1], where the original design parameters of all APS accelerators are listed. Over the years the parameters of the APS booster have changed, and this present document is a replacement which is updated periodically to reflect hardware changes.