I love this book written by Michael Ruhlman. Subtitled, "The Simple Codes Behind the Craft of Everyday Cooking," here is Alton Brown's forward which helps describe the content:
"Cooking, like so many creative endeavors, is defined by relationships. For instance, knowing exactly how much flour to put into a loaf of bread isn't nearly as useful as understanding the relationship between the flour and the water, or fat, or salt. That relationship is defined by a 'ratio,' and having a ratio in hand is like having a secret decoder ring that frees you from the tyranny of recipes."
It has been so interesting to learn about the ratios of breads, sauces, stocks, etc. and I also love learning about how different ingredients react chemically to each other. I don't know that I'll ever be able to give up recipes but this will hopefully help me to get better at just whipping things up in the kitchen. I would definitely recommend this book to anyone interested in the "why" as well as the "how" of cooking.