The authors identify the four major problem areas in the design of a Lisp machine to be (1) efficient function calling, (2) environment maintenance, (3) list access and representation, and (4) heap maintenance. They then give a classification of the Lisp machnes they have surveyed and examine how the designers of those machnes have tried to solve these problems. Trade-offs between different approaches are also discussed. This paper provides a good elementary introduction to run-time requirements of Lisp and Lisp machines. It is easy to read and does not require an extensive background on the part of the reader. I would like to add one reference that the reader interested in parallelism exploitation in Lisp programs may find useful [1].