100 Ideas That Changed Photography is part of the 100 Ideas That Changed... series, published by Laurence King. It was written by Mary Warner Marien, author of the excellent Photography: A Cultural History from the same publisher.
Marien follows the same format as 100 Ideas That Changed Film, an earlier entry in the series: 100 chapters, each with a single page of text accompanied by a full-page photograph. There are chapters devoted to a variety of camera types, photographic mediums, and genres, most of which are analogue rather than digital. There are also entries for different methods of photographic distribution, such as postcards, tabloids, and photo-sharing.
The book feels like an expanded version of The Visual Dictionary Of Photography, or a concise version of The Focal Encyclopedia Of Photography. The emphasis is on technology more than the art of the medium (in contrast to Photographers A-Z). A World History Of Photography (Naomi Rosemblum), The History Of Photography (Beaumont Newhall), and The History Of Photography (Helmut Gernsheim) have more historical context, though 100 Ideas That Changed Photography is useful as an overview of the subject.