If we like your proposal, we will ask to see the complete manuscript. If we like the complete manuscript, we will offer you a contract. Upon signing the contract, we will send you a check for your advance. Your book will then be scheduled for publication. If your book bombs, you still get to keep your advance.
Some authors never make more than the advance.
If you're sure your book is going to make you rich and famous, then you should try to get some mega-corporate international information conglomerate to publish it for you. From time to time, we publish an unusual book that finds a large audience, and that's great. Loompanics Unlimited is currently publishing between 10 and 20 books every year. We are constantly on the lookout for exciting new material, whether it's stuff that rattles the cage of consensus reality, or simply a how-to book on an unusual skill that is clearly and cleanly written. You don't have to write the whole thing before you ask us if we're interested.