Liquid Mexico by Becky Younman and Bryan Estep is a book I bought while researching tequila more than a year ago. The book is not a tequila directory by any means. It's a travelogue about a trip to Mexico to learn about different beverages there, from tequila to Corona to mixed drinks like the Margarita and the Michelada.
I can't say I learned much about the Margarita or Michelada or even tequila from reading this book, but that's not to say I didn't learn anything. In fact, I learned more about pulque and mezcal from Liquid Mexico than I had anywhere else.
Beyond that, the book was an engaging read, which each author taking turns writing chapters and them writing about their experiences learning about these beverages more than just reporting the dry facts after the research was done. So it's not a great research book beyond pulque and mezcal, but a good overview of Mexican drinks.