Harold McGee's On Food and Cooking: the Science and Lore of the Kitchen (second edition, 2004) is the single most useful and fascinating of the books I've read on the application of scientific knowledge to cooking. I loved the first edition from the 1980s, but the new one has far more information. Most books on food meerely repeat what the authors have read somewhere, or been told, regardless of whether it is actually the truth; Harold McGee is one of very few cooks who actually tests to see whether the claims are true.

Here's just one example of the sort of useful thing this book contains....

Page 163, in a chapter of all sorts of useful details on the chemistry and physics of cooking fresh meat, contains a box explaining how best to braise meat so that it is moist and tender. "The most important rule: never let the meat interior get anywhere near the boil." Cut it into large pieces, no less than one inch cubes. "Brown it very quickly in a hot pan....Start the pot with meat and cooking liquid in a cold oven, the pot lid ajar to allow some evaporation, and set the thermostat to 200 degrees F/93 C, so that it heats the stew to around 120 degrees F/50 C slowly, over two hours. Raise the temperature to 250 degrees F/120 C., so that the stew slowly warms from 120 to 180 degrees F/80 C. After an hour, check the meat every half hour, and stop the cooking when it is easily penetrated by the tines of a fork.