Hot springs, called Onsens in Japanese, are one of the greatest pleasures Japan has to offer. Due to its volcanic nature, the entire country is literally bubbling with thermal waters, and thousands of years of careful refinement has created a paradise of hot water soaking. Anyone coming to Japan should have a few onsens on their travel agenda, and a copy of "A Guide to Japanese Hot Springs" in their luggage. Anyone living in Japan should definitely have a copy on their bookshelf.
Authors Anne Hotta and Yoko Ishiguro have divided Japan into regions, then highlighted some of the best onsens in that area. Each onsen is sub-classified by location, properties of the water (the different types of mineral waters each boast a healing power,) around and about detailing special information about the onsen and its area, close accommodations and a few extras such as local foods and legends surrounding the onsen.
Although it was written in 1986, I have found the information to still be current, with all of the directions and accommodations still accurate. Of course, the prices have altered since then, but that is to be expected with every guidebook. Perhaps a good rule of thumb is to double every price in the book, for a more modern assessment.
The only flaw in the guidebook is a lack of ranking, or recommendations. Onsens are only classified by area, and there is no quick method for sorting which are the best. A "10 Onsens worth planning your trip around" section, a star-system, or something of the sort, would have been appreciated. Also, the background and history of onsens is slim, and could have been a more interesting section.
Overall, however, "A Guide to Japanese Hot Springs" is an indispensable book, and one that has greatly added to my time in Japan.