The details of the analysis, design, and operation of a Nd-glass-disk-laser amplifier which has been constructed at the Naval Research Laboratory are presented. Gain and fluorescence measurements have been compared to theoretical predictions; these show that 0.6-J/cm
3energy storage is achieved in the disk (assuming a cross section of

cm
2). The effects of unsuppressed parasitic oscillations are demonstrated and an effective method of preventing their occurrence is shown. The disk amplifier has demonstrated 320-J output in a 1-ns pulse with 110-J input.