But Brennan, who loves keeping score when it comes to the mutual fund industry, says that he's not monitoring sales of his recently published personal finance book, Straight Talk on Investing: What You Need to Know. Says Brennan, who wrote the book with the assistance of Vanguard corporate communications writer Marta McCave, "I'm sure there are people who think it's sport, but I've got a day job." Brennan's tome is a practical guide for small investors that champions the long-term, low-cost investment approach synonymous with Vanguard. The book also seems to open a new field of competition between Vanguard chairman Brennan and Vanguard founder and prolific book author Jack Bogle, who have had no love for each other since they bickered over succession issues several years ago. A couple of weeks after its publication, Brennan's book was impressively among the top 50 in sales on Amazon.com. Told this, Brennan, who spends his lunch hour on the Vanguard campus training for marathons, noted that soon after publication the book had actually been No 1. Not that he cares. "You'd hate to have it panned and be a failure," he finally concedes.