I finished the book and enjoyed it. Thanks David.
About the Prophecy. Many of the posters in this thread have commented on the various interpretations of the prophecy. One interpretation I haven't seen (or if I have I failed to parse it out) is that Sisko's marriage is not the actual cause of the sorrow, but instead leads to it.
Take option one. Sisko spends his life with Kassidy and "knows nothing but sorrow".
Option two, he does not and isn't miserable.
In option one he would be doing certain things in certain places simply because that was the life he was leading. In option two he would be in other places and doing other things. Simple change of circumstances could account for the difference in happiness levels. No causal relationship to his marriage is required.
Maybe if he hadn't gotten married then he would have done different things when returned from the Celestial Temple. Maybe he would have been in a position to save Vaughn, maybe he would have spent extra time with his dad and been there to save him rather than his not being found until the morning, etc...
Looking at the timelines from the outside the Prophets could have seen these differences and warned Sisko. If this is the case then leaving Kassidy would change the circumstances of his life and possibly avert further tragedy.
Of course, as has been pointed out previously, making decisions based on prophecy is fraught with danger. Interpretation is the key.
I could be wrong, but I seem to recall a paragraph in the book where Sisko is trying to describe (to himself or someone else, I can't recall) just what it was like in the Celestial Temple and how he became convinced that the Prophets were correct in their warning. He just couldn't make sense of what he had seen there.
In any case I have to disagree with those who think that Sisko came off as a "deadbeat dad". He KNOWS the Prophets experience the future. And he BELIEVES in the prophecies they produce. Whether you agree with his decision or not, whether you think he is wrong in his belief, it is entirely in the character that was developed over the course of the series.
Yes, Sisko is a family man. But he is also the Emissary of the Prophets. Even if they are not talking to him any more he believes in them and I would think the this particular prophecy had been eating away at him for some time. Any losses he suffered would be credited to it whether he really wanted to do so or not.
So that part of the story makes sense. Even if it is kind of depressing. I look forward to more development of Sisko in the future.
I also enjoyed the rest of the book. I especially like the Tzenkethi. Very cool