When the small cameras and portable projectors that used 16mm film stock emerged in 1923, they allowed--for the first time in history--the possibility that anyone could make, show, and watch movies. A foundational but largely forgotten film format that offered a suite of technologies, 16mm was a democratic alternative to the larger and more expensive 35mm technology used by the commercial film industries around the world. With the remarkable ubiquity and utility of 16mm, moving images came to be integral to the way we play, learn, fight, work, and document the world, seeding the path to our current world of portable technologies and personal media. To mark 16mm's first 100 years, the essays in this book consolidate and catalyse considerations of the uniquely important--but still surprisingly underestimated and understudied--role that 16mm has played in film and media theory, history, and practice. It has long been known that artists and activists relied on 16mm cameras and projectors as tools of experimentation, organization, upheaval, and advocacy. Chapters here revisit these assumptions but also survey its many varied and additional uses: delivering public service messages, promoting corporate public relations, boosting church attendance, preaching good hygiene, instilling efficiency, popularizing political candidates, spreading propaganda, exploring sexuality, and encouraging community dialogue. In short, tis innovative film format facilitated new forms of hobby, play, work, learning and creativity. From the local to the transnational, small gauge filmmaking and showing also became integral to colonialist, imperialist, nationalist, and multi-nationalist institutions and efforts. In effect, for 100 years now, this uniquely important film format upended and shaped creative, political, governmental, juridical, sexual, educational, recreational, informational, televisual, industrial, promotional, and experimental practices and activities. It was integral to the expansion and evolution of the audio-visual languages that are a common-sense element of our mediated world. Its histories serve as a crucial and telling bridge from past media practices to our present wherein mobile, adaptable, and flexible moving image and sounds continue to thrive.