Finite simple groups which projectively embed in an exceptional Lie group are classified! Bull. Amer. Math. Soc. 36 (1999), pp. 75-93 Robert L. Griess Jr. Department of Mathematics, University of Michigan, Ann Arbor, MI 48109-1003 and A. J. E. Ryba Department of Mathematics, Marquette University, Milwaukee, WI 53201-1881 Current address: Department of Mathematics, Queens College, CUNY, Flushing, NY 11367-1597 Abstract. Since finite simple groups are the building blocks of finite groups, it is natural to ask about their occurrence ``in nature''. In this article, we consider their occurrence in algebraic groups and moreover discuss the general theory of finite subgroups of algebraic groups.