An automated cartridge library has an essentially rectangular library frame which includes a frame front wall (22) and a frame back wall (24), and a library door (30) provided on the frame front wall. A transport actuator and guide region (90) is provided within the frame, the transport actuator and guide region including both a guideway along which a cartridge transport assembly (92) reciprocates and an actuator (124) which causes the cartridge transport assembly to rotate from a first transport position to a second transport position. A library front section includes a cartridge magazine cavity (50) and a entry/exit port module (54). A library rear section includes a region for tape drives (60) and an auxiliary cartridge magazine (70). Cartridge magazines (64) are insertable into the cartridge magazine cavity when the library door is opened so that a reference surface of the cartridges face the transport actuator and guide region.