WHEN SCIENTIFIC AMERICAN runs an article that addresses evolution in any fashion, we can count on receiving spirited replies from all areas of the opinion spectrum. This is no less true when the subject is technological, rather than biological, in nature. "Evolving Inventions," by John R. Koza, Martin A. Keane and Matthew J. Streeter [February], which discussed a way to develop new devices with software, served as something of a Rorschach test for people's views. Some saw the authors' work as strongly supporting the Darwinian explanation, whereas others thought that it did not support the idea of natural evolution. These and additional reactions to the February issue appear below.