Rick Riordan's The Mark of Athena was the #1 bestseller by a wide margin for the week ending October 7, according to Nielsen BookScan. The book sold 240,000 copies, more than double the #2 bestseller, Killing Kennedy by Bill O'Reilly, which sold 118,000 copies in its first week. The Casual Vacancy fell to #3 in its second week, dropping 32% to 105,000 copies sold for the week, bringing its two-week total to 261,000 copies at outlets tracked by BookScan.

In this week's issue of PW, we covered the state of big print debuts, noting that six books had debuted with sales exceeding 100,000 copies in 2012. That number is now eight thanks to O'Reilly and Riordan, the latter of whom now has two debuts over 100,000 this year (The Serpent's Shadow sold 116,000 copies in its first week earlier this year). The Mark of Athena's numbers make it the second-largest debut of 2012, trailing only No Easy Day.

Last week was good to other debuts, as well: John Sandford's Mad River sold 30,000 copies; Rachel Renee Russell's Dork Diaries 5 sold 23,000 copies; Arnold Schwarzenegger's Total Recall sold 21,000 copies, and Stephen Colbert's America Again sold 20,000 copies.