This article is about a very small subset of the positive integers. The positive integer N is said to be "perfect" if it is the sum of all its divisors, including 1, but less that N itself. For example, N = 6 is perfect, because the (relevant) divisors are 1, 2 and 3, and 6 = 1 + 2 + 3. On the other hand, N = 12 has divisors 1, 2, 3, 4 and 6, but since 1 + 2 + 3 + 4 + 6 = 16, rather than 12, 12 is not a perfect number. Ways and exercises for finding perfect numbers are presented. (Contains 1 table and 1 figure.)