The Film Developing Cookbook is much more useful to me. It answered more questions than I knew to ask. It tells you how developers work, and will help you pick the right developer. You can put much of its info to use even if you don't mix your own solutions from scratch. For any serious photographer who wants to understand film developing it is a must. It has opinions (with rationales)which is also of benefit.(posted 8534 days ago)The Darkroom Cookbook is more of a recipe book for mixing your own soups, and not really useful if you don't mix your own from scratch. (Not that I did not find it useful as well.) It balanced towards all photographic solutions (film developer, paper developer, stop baths, fixers, toners, reducers, intensifiers, ...).