I've enjoyed most of Straub's work, even the weaker books (Floating Dragon is likely the weakest--though still a good read), and have read Koko a few times. It does become pretty obvious who Koko is, but I never reallly found that detrimental to the read. Ther eis still teh question of finding him, and the bigger question of what pushed him over. Straub's strength, for me, lies in his style, a generally subtle and atmospheric one. An antagonist revealed or sometimes easily guessed (while I do understand that it's disappointing for many readers) has never been a problem for me in Straub's work because of the depth of the characters he builds. Even having guessed--at times easily--who the antagonist is, the tale continues to involve.

I never really minded the loose ends in Koko (or in some of his other books) and not knowing what happened in the cave seemed less important than knowing that something happened in the cave. Loose ends are often a plus to me, becuase they tend to keep me thinking about the book (or the motion picture) in which they hang. Finding the answers in other novels or short stories he's written is always interesting but I've never considered it essential.

The biggest problem I have with Straub is that he tends sometimes to try to force 'happy' endings. The epilogue of Koko just never worked for me and the relationship that blossoms has always rung false. He does the same thing in Ghost Story to some extent, with an epilogue that simply doesn't feel right with the rest of the book.