Weaver Adams, an American chess player authored the book "White to Play and Win". In this, and other books, he tried to prove that white has a decisive opening advantage after 1.e4.
Now we all now that white has a decisive advantage, but not after 1.e4 but after 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3. I am not 100% sure when black does not capture on f3, but I am pretty sure white wins by force when black dares to capture on f3.
The proof ? Not necessary - just believe it and you will see ( I wont go as far as saying that playing the Blackmar Diemer is like religion, but it sure comes close for some... ).
Details on Weaver Adams can be found on Wikipedia. Unfortunately he did not meet Emil Diemer - imagine what weird theories they could have come up with if only they co-authored a book ?!