According to one of Julia Margaret Cameron’s great-nieces, “we never knew what Aunt Julia was going to do next, nor did anyone else.” This is an accurate summation of the life of the British photographer (1815–1879), who took up the camera at age forty-eight and made more than twelve hundred images during a fourteen-year career. Living at the height of the Victorian era, Cameron was anything but conventional, experimenting with the relatively new medium of photography, promoting her own art though exhibition and sale, and pursuing the eminent personalities of her age—Alfred Tennyson, Charles Darwin, Thomas Carlyle, and others—as subjects for her lens. For the first time, all known images by Cameron, one of the most important nineteenth-century artists in any medium, are gathered together in a catalogue raisonné. In addition to a complete catalogue of Cameron’s photographs, there is information on her life and times, initial experiments, artistic aspirations, techniques, small-format images, albums, commercial strategies, sitters, and sources of inspiration. Also provided are a selected bibliography of publications on Cameron, a list of exhibitions of her work held both in her time as well as our own, and a summary of important collections where her pictures can be found.