*Concepts of Particle Physics.*Kurt Gottfried and Victor F. Weisskopf. Oxford University Press, New York, 1986. Volume I: 208 pp., illus. $13.95 PB. Volume H: 432 pp., illus. $45 HB.

More recently, a new generation of high energy accelerators has started to probe yet shorter distances. Those big machines will further scrutinize the "standard model" and most likely uncover new physics that will have to be appended to it. On the side of theory, a breed of "superstring models" has perhaps started a revolution that enthusiasts liken to the early days of quantum mechanics. By replacing the point particle approach with string variables at extremely short distances, they are able to unify "standard model" interactions with quantum gravity, a remarkable feat. In time, such models may radically alter our perception of space-time and cosmology.

In light of the rapid pace of new developments, it is not surprising that most physicists not actively involved in elementary particle research are out of touch with the more modern aspects of the subject and many textbooks are outdated. *Concepts of Particle Physics* (in two volumes) addresses that problem in the form of a pair of elementary textbooks that surveys various features of the "standard model" and its basic underlying principles.

The first volume overviews the field of particle physics in a readable nonmathematical manner. It is particularly well-suited for students and professional physicists outside of the field who wish to educate themselves about fundamentals and glean some appreciation of the more recent advances. A reader with an understanding of basic quantum mechanics and relativity should find it comprehensible and quite stimulating.

The second volume covers much of the same material as the first, but in more detail and with more mathematical sophistication; however, it is far from being formal. It concentrates on selected topics such as the bag model of hadrons, asymptotic freedom, and grand unification, and stresses basic concepts via their phenomenological implications. The second volume would make an excellent text for an advanced undergraduate course in modern physics or elementary particle physics. It is not detailed enough for a graduate course, but would provide a nice primer for graduate students just starting to learn the subject.

For many years, Gottfried and Weisskopf have been active contributors to elementary particle research. They have established reputations for their communication skills and intuitive approach to physics. These well-written books nicely attest to those abilities.