While most agents just want a Query letter, some ask for a Synopsis or Overview, some ask for your first 3 Chapters and some ask for your Proposal. Before you send out your Query letter, have your Proposal completed and a your first 3 Chapters in excellent form. "Good enough" won't cut it. Remember, it's all they see of you and your work is one of hundreds submitted. Google Query Letters to Agents and Book Proposals and you'll get a good idea of what's required. Again, some agents want you to fill in their own form so a lot of this goes out the window. Being prepared is important, especially if an agent is interested.

I had the interest of an agent who liked my Query, but my chapters weren't as good as they could be and lost that agent. Please learn from my mistake.