I've been listening to "How to Publish Your Book," offered by The Great Courses. In an early lecture, the speaker lists various resources an author should turn to in order to research agents. She says the fee-based resources offer higher quality information, and she first mentions Writers Market and then Publishers Marketplace. Though she talks about how PM gives great insight into who's buying what and who's active, I'm still unsure why PM would be worth the money. Why not simply use AgentQuery and/or QueryTracker (which she later mentions)? Has anyone used PM to develop their "target agent list"? If so, can you lay out the reasons why you found it more helpful than AQ and QT? Thanks!