Abstract: An automated storage library includes a robotic picker which moves linearly between linear and/or carousel storage shelves to transport data storage cassettes between the shelves and a data transfer device. The picker arm can swing in a vertical arc to access the tape stores on either side of its linear path. The arm also has at least one rotatable wrist and a pair of end effectors. A data storage cassette may be extracted from a data transfer device, the wrist rotated 180.degree., and a new cassette inserted. This reduces the number of times the robot has to visit the tape stores. The vertical arc movement of the picker arm provides for accurate orientation of the effectors with respect to the shelves and the data transfer devices.