"Oh, he wrote that
only to make money!" You hear those words whenever someone wants you to dislike an author, no matter what the book and no matter who wrote it or why. In the world of non-fiction, those words are flung at all writers who take a non-conventional view of history, science or society. If a would-be author even attempts to research a work about current events, he'll run into that phrase on repeated occasions. "All you care about is the almighty dollar..."
Here's the truth.
A writer is very
lucky if he makes $5,000 from a book -- and if he writes a heavily-footnoted work of non-fiction, the work may take years to complete. Greeters at Walmart do better.
Wanna be a writer? Jump on in; the water's fine.