Every three months I've been looking at Barnes & Noble's quarterly conference call to get some insight into recent book industry trends and to see which books were the big sellers over the past few months and which are expected to be big in the coming months. Barnes & Noble's second quarter ended August 4th. Almost certainly, it'll be the last time that the bookstore chain will experience the rush of sales generated by Harry Potter, and the company made the most of it, riding the Boy Wizard to results that came in at the high end of its forecast and meeting Wall Street estimates that had been padded with high expectations for the final Potter installment. With Potter coming out late in the quarter, however, the vaunted "Potter effect" was only in play for the final two weeks of the period.Here are the highlights from CEO Steve Riggio on the Q2 conference call (courtesy Seeking Alpha):Harry Potter drove sales higher but knocked Barnes & Noble's profit margin lower thanks to "significant discounting." The book was marked down 40% instead of the usual 30%.More Harry - selling well but tailing off: "The book sold even better than our expectations in its first days on sale, but in the following weeks, sales of the book tailed off quite a bit, as it was available in abundant quantity in a large number of mass merchants and non-book store retailers. Nevertheless, Harry Potter and the Deathly Hallows continues to sell well. It remains our number one best selling hard cover title, and we expect to sell hundreds of thousands of copies through the end of the year."But perhaps the Potter party isn't over yet: "We believe that sales of the entire series are going to continue to dominate children's bestseller lists for many, many years. While the Harry Potter cycle may be complete for those who have read the entire series, it is yet to be discovered by millions of readers now and in the years ahead."Moving beyond Potter, Barnes & Noble saw "a mix of expected bestsellers from brand name writers and the emergence of a few sleepers." The expected: Khaled Hosseini's A Thousand Splendid Suns, Janet Evanovich's Lean Mean Thirteen and James Patterson's two books, The Quickie and The 6th Target. The sleepers: Conn and Hal Iggulden's The Dangerous Book for Boys. Thomas Cathcart's Plato and A Platypus Walked Into a Bar, Denise Jackson's It's All About Him, and Elin Hilderbrand's Barefoot. The fourth Barnes & Noble Recommends selection, Paulette Giles' Stormy Weather also saw "strong sales."Riggio also mentioned a recently published book, Eclipse by Stephenie Meyer. Apparently vampires never go out of style because according to Riggio, the book has "catapulted Stephanie Meyer into the ranks of mega bestselling authors. It outsold Harry Potter, toppled it from the bestseller list and it actually became the fastest-selling teen novel in our history."And finally, Riggio previewed third quarter releases that are expected to be big: Bill Clinton's Giving, Alan Greenspan's The Age of Turbulence, the late David Halberstam's final book, The Coldest Winter, John Grisham's Playing for Pizza, Alice Sebold's The Almost Moon, and the tie-in book for the Ken Burns WWII PBS documentary airing this fall.