Matroids are an abstraction of several combinatorial objects, among them graphs and matrices. The word matroid was coined by Whitney in 1935 in his landmark paper "On the abstract properties of linear dependence". In defining a matroid Whitney tried to capture the fundamental properties of dependence that are common to graphs and matrices. Almost simultaneously, Birkhoff showed that a matroid can be interpreted as a geometric lattice. Maclane showed that matroids have a geometric representation in terms of points, lines, planes, dimension 3 spaces etc. Often the term combinatorial geometry is used instead of simple matroids. However, combinatorial geometry has another meaning in mathematical literature. Rank 3 combinatorial geometries are frequently called linear spaces. Matroids are a unifying concept in which some problems in graph theory, design theory, coding theory, and combinatorial optimization become simpler to understand.
Books. This page has a chronological list of matroid books including collections of papers, applications and generalizations. A good textbook on matroids is James Oxley's book Matroid Theory. Click here for a Postscript file containing an errata and update on conjectures, problems, and references.
Surveys. This page has a chronological list of survey papers related to matroids. Many of them serve as entry points into particular matroid topics or matroid generalizations. These papers also have lengthy bibliographies and many open problems. There are links to copies of some papers which serve as a quick overview of the subject.
Home Pages of people in Matroid Theory . This page has list of mathematicians working in matroid theory with links to their home pages.
Oid - a software system for experimenting with matroids. This page has information on Oid and links to other matroid and combinatorial software.
MegaMath at Los Alamos
Daniel Sander's Graph Theory Resources
Jerry Grossman's Erdös Number Project (in collaboration with Patrick Ion and Rodrigo De Castro)