It’ll be a late night tonight for “muggles” all across the Hawkeye State as the new Harry Potter book will be released just after midnight. The sixth book in the seven-book series will be welcomed by throngs of readers at special sales from Sioux City to the Quad Cities. Linda Johnson, spokeswoman for a Des Moines mall, expects hundreds of visitors, costumed in capes and waving wands. She says the Waldenbooks store has 800 reserved copies of the book, in addition to hundreds more copies for other buyers. The pajama party includes a ghostly host of events staring at 10 P.M. and will include someone reading aloud from “Harry Potter and the Half-Blood Prince,” but that reader may need magic to make it through all 672 pages without a break. Johnson says the book may have been written for kids, but she obsesses on the series too, as do millions of other adults.She says she’s read every one of the books and decided to refresh her memory by starting about a month ago to re-read books three, four and five in preparation for tonight’s appearance of book six.