Severus glanced up when Weasley spoke, undeniably a little irritated on reflex at having his attention distracted from the words on the page. He held the book up for Percy to see the title emblazoned on its spine. He frankly had no idea why Weasley was talking to him in the first place -- it was hardly as if they had anything in common, after all. They were not even from the same time period, never mind the same House, or with the same group of friends. Severus could count the number of times he had spoken to Percy Weasley on no more than two hands.
"It was the only title of interest that I could find in the library here," Severus said, putting the book back down, turning his attention to its pages once more. Not that he needed to defend the fact that he was reading a Muggle-written book. It was none of Weasley's business, after all.