In this sixth volume in Sky and Telescope's Library of Astronomy, the husband-wife astronomer-geologist team have collected many of the important reports or notes on stellar evolution that have appeared in the magazine over the past thirty years. Dominating this research is the all-powerful Hertzsprung-Russell diagram which embodies the relationship between a star's magnitude (or luminosity) and its spectral type. Most popular accounts of the birth and death of stars stop here, characterizing a star's biography by its position along the ""main sequence, or among the red giants or white dwarfs flanking the diagonal distribution. Readers of this volume will find this only a starting point for sophisticated discussions of nuances, exceptions, theories and countertheories which probe not only the age of the galaxy, but the distribution and frequency of chemical elements, the order of their production and the anomalies that exist among variable stars in older and newer populations. Not a book for the novice, although occasionally lightened by longish summary articles by the late Otto Struve, a major contributor to almost emery aspect of astronomy.