Stephen King criticised the reactions of some reviewers to the books, including McCauley, for jumping too quickly to surface conclusions of the work. He felt this was inevitable, because of the extreme secrecy before launch which did not allow reviewers time to read and consider the book, but meant that many early reviews lacked depth. Rather than finding the writing style disappointing, he felt it had matured and improved. He acknowledged that the subject matter of the books had become more adult, and that Rowling had clearly been writing with the adult audience firmly in mind since the middle of the series. He compared the works in this respect to "Huckleberry Finn" and "Alice in Wonderland" which achieved success and have become established classics, in part by appealing to the adult audience as well as children.