Television Treatments

Well, here is a new one! I have been asked to help develop and write a treatment for an idea for a television show. This is something I have never done. I am doing some research on the process and on what should be included in a treatment (title, logline, synopsis). Have you ever written a treatment? Do you know the process? Do you know anything about registering with the WGA? Any information from my loyal readers would be greatly appreciated!