I went digging on this, because I thought you were wrong. Turns out the official book name is indeed singular, and in fact I tracked this singular usage all th

I went digging on this, because I thought you were wrong. Turns out the official book name is indeed singular, and in fact I tracked this singular usage all the way back to Athanasius 39th festal letter in AD 367, listing the accepted books of the New Testament - "the Revelation of John". "The Revelation" is also the first word of the book in greek. (Ἀποκάλυψις or apokalypsis) So thanks for the enjoyable rabbit trail.