The potentials for peacetime use of nuclear energy are vital to everyone. Whether Dr. Hughes of the Brookhaven National Laboratory, with his somewhat formal, didactic style can reach the layman, time only will tell. He speaks with obvious authority, and, with reasonable concentration on the part of the reader, he is fully understandable and richly informative. He appeals immediately to the kind of person, perhaps ordinarily with college background or its equivalent, who wonders; ""What is nuclear energy? How may it be used? What are its potentialities?"" And he does it without depending on equations -- or on glamour or imagination. The exposition is solid, occasionally tainted with stodginess, but on the whole very readable and logically satisfying. One ends with answers to moot questions, with respect for Dr. Hughes, and with a substantial measure of gratitude. For these are things we need to know.