Chef and Food Researcher
This is by far the cookbook that has helped me more in perfecting skills at early stages of being a cook, and afterwards when it came to teaching as well. It's the manual that all cuisine students are given when studying in France. If I had to recommend only one book to someone wanting to learn cooking, this would be it (even if that would imply learning a few French words!). You can easily open a few successful restaurants if you follow that book: It is very precise in techniques and recipes, both savoury and sweet. Also everything in terms of regulations and safety. Another jewel