In 1995, Michael Treacy and Fred Wiersema, the authors of a book called "The Discipline of Market Leaders", colluded to manipulate their book onto the best seller charts. The authors allegedly purchased over 10,000 copies of their own book in small and strategically placed orders at bookstores whose sales are reported to BookScan. Because of the benefits of making "The New York Times" Best Seller list (speaking engagements, more book deals, and consulting) the authors felt that buying their own work was an investment that would pay for itself. The book climbed to No. 4 on the list where it sat for 15 weeks; it also peaked at No. 1 on the "BusinessWeek" best seller list. Since such lists hold the power of cumulative advantage, chart success often begets more chart success. Although such efforts are not illegal, publishers consider them unethical.