Here’s an interesting Wall Street Journal article by Carl Bialik (“The Numbers Guy”) on how authors (and their public-relations firms) try to push a book to No. 1 on Amazon.com or Barnes&Noble.com: For $10,000 to $15,000, you, too, can be a best-selling author. New York public-relations firm Ruder Finn says it can propel unknown titles to the top of rankings . . .