This book isn't very big on text, but it does offer a good section of the development history of the Su-25. The vast majority of the book is devoted to photographs. Mostly of the Su-25UTB (of which pictures tend to be rare elsewhere) and all of the other later two and single-seat variants of the Grach/Frogfoot. It must be said that while it covers all the major variants and it's very photo intensive, the book isn't very big and only spends a few pages on each version.I'd call this a great follow-on reference for Su-25 enthusiasts, but it's far from the end-all-be-all reference it could be.