Why would you want one book? Can you even imagine trying to search through such a thing, or updating it? It's far better to have textbooks for each subject. As

Why would you want one book? Can you even imagine trying to search through such a thing, or updating it? It's far better to have textbooks for each subject. As for open source textbooks, here is one such initiative: https://openstax.org/ https://openstax.org/