I must acknowledge my family; my parents, John and Sherry Rawlins, for never giving up on me, even when I changed my mind thousands of times, my grandparents, Barb and Kenn Dubbels, for being a continued source of inspiration and love, and my sisters, Anne and Becky Rawlins, for all the laughs and rants. I owe a debt of gratitude to all my friends for being there and listening to me, especially my long-suffering roommate Chelsea Kelley for keeping me alive and well-fed. I wish to thank my advisor, Dr. Jeffrey N. Agar for his support and management throughout my Ph.D. The training and expertise I received because of this lab is immeasurable and I am grateful for his hard work. Thank you to Agar Lab members past and present for being great lab mates. Thank you to Daniel Donnelly for his friendship, cheery disposition, and for being a prodigious collaborator. Thank you to Dr. Jeniffer Quijada and Dr. Jared Auclair for their training and mentorship as I grew to be a better mass spectrometrist. Special thanks to Ed Luther for his guidance, cytometry expertise, and entertaining demeanor. Thank you to Dr. Nathalie Y.R. Agar for allowing me to work in her lab and use her instruments at Brigham and Women's Hospital. Thank you as well to her whole lab group, especially Elizabeth Randall, Michael Regan, Amanda Clark, Bobby Basu and Begona Gimenez-Cassina Lopez. I wish to thank Dr. David Calligaris for being a great mentor and teacher at BWH early in my graduate school career. I feel fortunate to have been given the chance to hone my skills in MALDI MSI under their guidance.