Matroids are discrete mathematical objects that generalize important concepts of independence arising in other areas of mathematics. There are many different important classes of matroids and a frequent problem in matroid theory is to determine whether or not a given matroid belongs to a certain class of matroids. For special classes of matroids that are minor-closed, this question is commonly answered by determining a complete list of matroids that are not in the class but have the property that each of their proper minors is in the class; that is, minor-minimal matroids that are not in the minor-closed class. These minor-minimal matroids that are not in the minor-closed class are called excluded minors. In this thesis, we construct interesting minor-closed classes of matroids and then characterize them by determining their complete sets of excluded minors
