Contents

13 March 1987
Vol 235, Issue 4794

About The Cover

A composite image of Markarian 348, the largest known galaxy. The cold, neutral hydrogen is shown in blue; the stars in the galaxy are shown in red. This is a Seyfert galaxy (one of the 5% of galaxies that have unusually active centers) with dimensions 310 by 390 kiloparsecs, or 13 times the size of our own galaxy. See page 1367. [S. M. Simkin et al., Michigan State University, East Lansing, MI 48824]