Thanks are due, first, to Randy McEntaffer, for your mentorship, advice, friendship, and patience throughout these last five years. Without an advisor of your caliber this would not have been possible. To the other members of the thesis committee, Cornelia Lang, Phil Kaaret, Craig Kletzing, and Frank Krennrich, thank you for your time and your helpful suggestions. To our collaborators, Miroslav Filipovic, Luke Bozzetto, and Evan Crawford of the University of Western Sydney, thank you for contributing your time, your data, and your expertise on radio analysis and interpretation.