A perfect graph is a type of graph in graph theory where the chromatic number of every induced subgraph equals the size of the largest clique in that subgraph. This means that the minimum number of colors needed to color the graph's vertices, so that no two adjacent vertices share the same color, matches the size of the largest complete subgraph (clique) within it. Perfect graphs include several well-known classes, such as bipartite graphs and circular arc graphs. The concept was introduced by Claude Berge in the 1960s, and it plays a significant role in various areas of combinatorial optimization and theoretical computer science.