  In this paper we study the finite groups in which every element has prime
power order, briefly them EPPO-groups. The classification of EPPO-groups is
given including the cases of solvable, non-solvable and simple EPPO-groups.
This paper is published in Journal of Yunnan Education College, no.1(1986),
p.2-10 (in Chinese). Translate it to English is helpful for readers for citing
some conclusions of this paper. For example, the result of solvable
EPPO-groups(see Theorem 2.4 in the text) is detailed more than G. Higman's
conclusion (see reference 1 in this paper).
