Table of Contents

Books
Symbol Sourcebook: An Authoritative Guide to International Graphic Symbols by Henry Dreyfuss

Letters

Features:

From the Gene to Behavior
by Seymour Benzer

So It's Spring

The Shape of Space
There is only one universe, doing—as far as we can tell—rather simple things. But do we understand those things?
by James Gunn

Research Notes
Electrical Conductance in Membranes
Slime Mold and Differentiation
Sound Waves on the Sun
Pioneer 10—A Small Spacecraft with a Big Job

J. Holmes Sturdivant—1906-1972
A tribute by George Hammond

Campus News:

The Month at Caltech