Before subbing my MS to editors, my agent asked me to write a query for the book. Not the whole "Dear Editor, boy do I have the perfect book for you blah blah blah" part, just the part about the book. He then edited it to his satisfaction and wrote the rest of the letter.
Aaaanywho, one of my friends said that's weird because she thinks agents tend to write all of the letter themselves without any input from the author. Is that true? I'm just curious to know how many agents do this.