We present an efficient method for Fast, complete, and accurate detection o
f unstable periodic orbits in chaotic systems. Our method consists of an it
erative scheme and an effective technique for selecting initial points. The
iterative scheme is based on the semi-implicit Euler method, which has bot
h fast and global convergence, and only a small number of initial points is
sufficient to detect all unstable periodic orbits of a given period. The p
ower of our method is illustrated by numerical examples of both two- and fo
ur-dimensional maps. [S1063-651X(99)06711-2].