RedBlack implements basic capabilities of Red-Black trees, an efficient kind of balanced binary tree. The particular algorithms used are adaptations of those in Corman, Lieserson, and Rivest's <EM>Introduction to Algorithms</EM>. This class was inspired by (and code cross-checked with) a similar class by Chuck McManis. The implementations of rebalancings during insertion and deletion are a little trickier than those versions since they don't swap Cell contents or use special dummy nilnodes.