I first heard about this book when it was released "a while ago" (ie. I can't remember when), but now that I managed to track it down at the library, I'm thankful I didn't forget about it. Simply put, Michael Ruhlman does a fantastic job of breaking down the importance of the ratio in everyday cooking. You may or may not notice, but the majority of recipes out there, especially in the baking world, all rely on precise ratios of ingredients (usually involving flour, eggs, sugar, and fat of some sort) in order to create the finished product we are expecting. Most people (myself included) hadn't realized this (or haven't gone to pastry school) and as such develop pathological inflexibilities when it comes to following recipes, or convincing themselves that they just Can't Bake It. Up until a month ago, I had a Pathological Fear of Pie Crust. True story.
Ruhlman abandons the traditonal cookbook approach, because after all, this isn't really a cookbook. This book is about understanding fundamental ratios. Once you can grasp the ratio of a cake or dough or crust, it's like you've been liberated. It doesn't matter what kind of flavours or accessory ingredients you add, as long as you maintain the ratio, you will always get the proper finished product.
Or, as the inside cover puts it, "When you know a culinary ratio, it's not like knowing a single recipe, it's instantly knowing a thousand."
So, Ruhlman does an excellent job of explaining what the ratio of each "recipe" is all about, and offers some helpful hints on varations you can try. For example, the ratio for Bread Dough = 5 parts flour : 3 parts water (plus yeast and salt). Once you have that down, you can extend it to make garlic bread, white sandwhich bread pizza dough, etc. Basically, the possibilities are endless!
I love this book for this exact reason. I love to bake, but because I have no formal training I find myself more or less hoping for the best, especially with new recipes, and especially with things like pastry. But, now that I can have a better understanding of the ratios that lead to the finished product, I'm really free to experiment with the knowledge that I really can't go wrong. Which is a great feeling.
Fun fact: Did you know that a pound cake and a sponge cake both have the exact same proportions of eggs : fat : sugar : flour (1:1:1:1)?! Isn't that crazy! The difference is all in the order that you add the ingredients, not necessarily the ingredients themselves.
That alone, to me, makes the book worthwhile. Geek out!