I was reading about this with wine gunk. Some people were using it to start off their next batch. I was curious about this, because it was to my understanding the yeast died after it reached the max % alcohol for that yeast, or consumed all the sugars in the alcohol. I also heard from the fermentation store that it does make good hatden fertilizer, but can make your dogs sick if they eat it from the hops. Haven't had time to dig into the dog aspect of it yet.
Was this book you're referring to on beer or wine brewing? Do happen to have a title and author? It sounds like a wonderful gift for the hubs.