There have been many books published about Japanese gardens, but The Gardens of Japan (Frances Lincoln Ltd, 2017) by Helena Attlee is right up there near the top of my list. (FYI, the hardback was published in 2010, and this new edition is the paperback).
Although it includes well-known Japanese gardens like Ryoan-ji, the major emphasis in the book is on Japanese gardens off the beaten track -- ones you certainly might miss on a regular tourist trip. As the author notes in the introduction, different garden styles marked different eras in Japanese history. "Consequently," she says, "in Japanese gardens old and new are interleaved and inseparable, rather than being, as Japanese garden historian and author Teiji Itoh puts it, 'piled up like strata in an archaelogical excavation.'"
Nineteen of the 28 gardens profiled in the book are in and around Kyoto, the rest spread around the country. Each entry includes a number of stunning photographs and a brief description of the garden and its major attributes. I was particularly fascinated by Ritsurin-koen in Takamatsu, At the foot of a mountain, famous because it's known for the Japanese art of niwaki, or sculpting trees. The garden has more than one thousand pine trees, six ponds, miniature hills, rocky islands and plains as well. If you're planning a visit to Japanese gardens, this one, and many others in this book, will definitely be on your itinerary -- and not on everyone else's.