In advance of Hillary Clinton's June 29 appearance at Vroman's in Pasadena, the bookstore's Linda Urban tells Tim Rutten: "We've already had 500 requests for signed books, more than I can remember and I've been doing this for 8 1/2 years. We had 7,000 people turn up for Howard Stern's book signing and we only had 100 book requests before that event....When Monica Lewinsky's book came out, we had three television crews in here all day, desperate to film somebody buying the book. Almost nobody did " The column puts the Clinton blockbuster and Friday night's release of the new Harry Potter book in the context of the book industry's hard times.