Modeling biological evolution on a computer began in the 1960s with evolution strategies in Europe and genetic algorithms in the United States. Genetic algorithms were introduced to the antenna community in the early 1990s. Since that time, they have become ubiquitous in computational electromagnetics and standard options on commercial software packages. Other biological design methods based upon biological processes in nature have also been introduced. This article provides an introduction to genetic algorithms, particle swarm optimization, and ant colony optimization. Several examples of antenna array optimization are presented to illustrate the power of these algorithms. © 2014 ACES.