Although there are rumors concerning a Common-speaking meowth writing his memoirs, the truth of the matter is that no book we know of was written by pokémon, I’m afraid, and it’s unlikely that there will ever be such a book. For one thing, pokémon communicate in an entirely different language to our own, one that has yet to be translated by humans, and we as a species aren’t yet at the point where we can coax pokémon that can communicate across that barrier (either by speaking Common or by using telepathy) to work on a long-term basis as translators.
Yes. Yes, that’s why there are no books written by pokémon. Not the fact that it’s physically difficult for pokémon to write long-form in the first place. —LH
You think I’m joking, but I’m really not this time. —Bill
The Pokédex According to Bill 