To Heinlein's surprise, "Starship Troopers" won the Hugo Award for Best Novel in 1960. It has been acknowledged as one of the best-known and most influential works of science fiction. The novel is considered a landmark for the genre, having been described by a 1960 review as one of the ten best genre books of 1959, in a 2009 review as a key science fiction novel of the 1950s, and as the best-known example of military science fiction. It was also a personal landmark for Heinlein; it was one of his best-selling books, and is his best-known novel. The novel has been described as marking Heinlein's transition from writing juvenile fiction to a "more mature phase" as an author. Reviewing the book with others written for children, Floyd C. Gale of "Galaxy Science Fiction" wrote in 1960 that "Heinlein has penned a juvenile that "really" is not. This is a new and bitter and disillusioned Heinlein". Rating it 2.5 stars out of five for children, 4.5 stars for adults, and "?" for civilians, he believed that the novel would be "of exceptional interest to veterans with battle experience ... but youngsters will find it melancholy and verbose". Conversely, Michael Moorcock described it as Heinlein's last "straight" science fiction, before he turned to more serious writing such as "Stranger in a Strange Land".