More than any other, this book taught me how to cook. Peterson's brilliance lies in his ability to weave together history, science, technique, opinion, and (finally) recipes, into a narrative that makes compelling reading.
You could use this as a textbook, a recipe book, a reference work, or as bedtime reading. Ideally as all of these. It's compelling, comprehensive, authoritative. I love it.
I've read the first and second editions, and so can only comment on these. The first has a strong French focus (ancienne, classical, and nouvelle). The second edition expands into other cuisines, reflecting changes in culinary education globally—classical French is no longer seen as the fount from which all culinary wisdom flows. It's an important update, but I do miss the taxonomic tree diagrams of French white and brown sauces.
Missing from these books is the culinary knowledge of the past 20 years, including pressure-cooker and sous-vide extraction techniques, modern hydrocolloid thickeners, and techniques using whipping siphons. If these are included in the 4th edition, I'll have to run out and get it. In the mean time, my go-to has been Nathan Mhyrvold & company's Modernist Cuisine series.