Today, an unashamed plug for the Author’s Guild (no, I don’t get a commission). If you're a writer you should be a member. Why? Here’s one point, directly from the AG:
“Ask any experienced author: book contracts can be riddled with traps for unwary writers. Authors Guild attorneys have more than 45 years of experience with media contracts. We'll review your book contract before you sign, let you know whether it meets industry standards, and tell you how it can be improved. Have an agent? Excellent. Consider us another resource in getting the best deal possible.
Contract reviews are free for members. Dues are $90 for the first year – after that, dues vary according to writing income, but most authors continue to pay $90.
Join 8,000 of your colleagues now, before you lay pen to contract. Visit www.authorsguild.org to apply.”
Having them review one book contract for you is worth more than a year’s dues. Bargain! At their web site they also have a blog, accessible to you whether or not you're a member, on which they chronicle the major legal issues and cases relating to writing.
(Of course another useful tool is my book, "Your Writing Coach," published by Nicholas Brealey and available from Amazon and other online and offline booksellers--it's also Brealey's number one Kindle title.)