This is a very informative book about fermenting foods the old fashioned way. It runs the gamut from vegetables, to breads, to grains and porridge, and in between. There's a bit of history which I didn't read much of yet because I was excited to get to the useful stuff, but will be interested in reading through later. Some information about the health benefits of fermented foods too.
This is not a scientific or precise manual. This is great for adventurous and intuitive cooks who like to try things and see what happens. There are recipes, but sometimes you have to use your brain and figure out the best methods for your specific situation.
I've done porridge, dosas, improved my bean cooking methods, and made 2 loaves of bread from my own sourdough starter so far.