Matroid theory draws heavily on both graph theory and linear algebra for its motivation, its basic examples, and its notation. The ideal background for a student using this book would include undergraduate courses in linear algebra, graph theory, and abstract algebra. However, I have used the book with students having no previous expoeure to graphs and very little abstract algebra; most of the ideas needed from these areas, particularly in the earlier chapters, are relatively straightforward. The rest of this section introduces some notation and outlines some basic concepts. After reading this, the reader who is familiar with vector spaces should have enough background to handle at least the first half of the book.