Given how long this book has been around and how hard it is to find online, maybe I am missing something that would lower my rating.
But, holy cow! This gives you a kick in the butt to start refining your own alcohol fuel! The book is center around what is essentially a mini green house that evaporates alcohol from your ferment while letting most of the water pass through. Imagine a shallow box tilted at an angle towards the sun lined with black clothe: your brew is trickled in the top at a rate that allows only the alcohol to evaporate. The alcohol then condenses on the glass panel and runs into a separate catch that empties your much higher proof liquid into a jar.
The book goes into other considerations regarding how to ramp up efficiency, how to work when the sun's not out, and how to scale up your refinery.
I haven't tried it though, but I want to. If nothing else, you could use the same setup to purify your own water.