I like these-
Rick Bayless Mexican Kitchen
The Essential Cuisnes of Mexico by Diana Kennedy
Rosa Mexicana by Roseina Howard
The Wahaca ones have easy recipes but they aren't that authentic despite Miers claims to be. They have been adapted.
I was brought up in Mexico and Central America and love the cooking of my adopted homelands.
The first two books are still not difficult although some of the ingredients might have to be ordered online.