I hear from writers all the time who have legal concerns associated with their writing. Sometimes it's a copyright question, something to do with permissions to quote from other's materials or even more serious issues. Every writer needs a volume nearby to help answer all those sticky legal questions. The best book I've found on the subject is Author Law A - Z: A Desktop Guide to Writers' Rights and Responsibilities, by Sallie Randolph. It covers such subjects as kill fees, negotiating an advance, finding an agent, agent's and publisher's contracts, copyright infringement, tips for smart negotiating--and so much more. You can order this must-have resource in my online bookstore. Go to http://www.stuartmarket.com/, click on "Bookstore." then "Legal Issues," and scroll down to the title.
If you are having more serious legal problems and need a lawyer versed in publishing law, I can also recommend Sallie Randolph who will advise you or your lawyer on this specialized area of law. Contact her at firstname.lastname@example.org; http://www.authorlaw.com/.