Joshua Lappen has successfully defended his DPhil thesis on 'Cultures of Power: Electrification, Politics, and Visibility in Greater Los Angeles'. Stephen Tuffnell, Josh's internal examiner and RAI Senior Fellow, praised the thesis as "a stellar, original, and imaginative contribution to the histories of electrification in Los Angeles and the United States, and to the histories of capitalism and technology for the profession as a whole. The thesis stands out for the quality and depth of Josh's archival research, for Josh’s masterful storytelling and humanizing of a story of technological and bureaucratic innovation, and, above all, for its proposal of an entirely new sociological model for understanding electrification: electric visibility. As Josh tells it, electric visibility was a distinctive regime of social and political relations expressed through electrical architecture and aesthetics, corporate boosterism, and municipal politics that placed electricity at the centre of the life of Angelenos even after electricity had ceased to be a novel technology. This important work will be field changing."