Some agents (and most editors) ask for a chapter synopsis first. Now I've read/heard conflicting reports on how long a synopsis should be. If read several places that a synopsis should be just a few pages long. I've also read that a synopsis should be as many pages long as the book has chapters. What have you heard?
My book has 18 chapters and my synopsis is 17 pages long, which I'm afraid is lengthy and unweildy. I'd prefer to send as much as I can to an agent, but not if a bulky synopsis turns them off.