The one I bought is a cookbook. In addition to presenting ratios, it provides recipes for different dishes. Its primary focus is to get you to cook using ratios but there are recipes to show you how ratios work.
I know...I was just kidding. I read cookbooks like others read fiction. They are fascinating treatises on my favorite subject...FOOD!
I have said it before but... I am not in total agreement with the ratio thing. I do think it is an interesting perspective, and would be a fine place to start on things, but...
It at least gives you a base to start on when you want to wing something. Creation of new recipes does depend on a solid base of understanding how things work together. There is still enough room to do moderate adjustments to work in high/low altitude and high/low humidity.
I recently purchased: The Practical Step-by-Step Guide To BAKING BREAD by Christine Ingram and Jennie Shapter, I'm loving it. It is written simply and very easy to follow. The first bread I tried was a Cheese and Onion Loaf. To die for!
For everything you ever needed to know (and more!) about making bread, there is only one book. Elizabeth David's "English Bread and Yeast Cookery" (don't be put off by "English". It's more far reaching than that).