The intent of this article is to briefly review ruby (Cr3+ in Al203) and neodymium in yttrium-aluminum garnet (Nd3+ in Y3Al5012 - "YAG") lasers by stating theii present operating characteristics in the most common and useful modes of operation, and then commenting on the factors that limit their performance and what, if anything, can be done to improve upon them. Other reviews of ruby (Refs. 1,2) are recommended for details concerning its operation (output characteristics, mode struc-ture, properties of ruby, etc.). Several reviews of other crystalline lasers have been written (Refs. 3-5) but the best review of Nd:YAG lasers is by Gallagher (Ref. 6); further sources of information on this laser can be found in the current literature (Refs. 7-19).