And guess what? You can still find the PDF floating around the internet today. But before you go hunting for that digital grail, let’s talk about why this 40-year-old book is suddenly more relevant than your sourdough starter.

Published in 1976 by the team behind the legendary The Book of Tofu , this isn't a pamphlet of soup recipes. It is a 450-page encyclopedia dedicated to one ingredient. It covers the 2,000-year history of miso in Japan, the science of koji (the magic mold), and—most importantly—how to make it at home in five-gallon batches.

However, the information in the PDF is timeless. The calculations for salt-to-soybean ratios haven't changed. The troubleshooting guide for "Why is my miso bubbling?" is still the best on the internet.