I just finished the book. The first as Sci-fi I've ever read. One aspect of the book that confused me was the concept of Mercerism. The Androids and Buster Friendly state that Mercer is a hoax who in reality is a drunk, however later on in the book Mercer appears to Deckard and saves his life, then there's the weird identity crisis Deckard suffers where he believes he Is Mercer himself and gets hit with an actual stone, leading me to believe he is in fact Mercer or he is hallucinating due to over exhaustion and the previous events. I'm a little confused as to if Mercer is in fact a messiah or a fake, did I miss something?