Diane Johnson, who co-wrote the screenplay for "The Shining" with Kubrick, notes that he "always said that it was better to adapt a book rather than write an original screenplay, and that you should choose a work that isn't a masterpiece so you can improve on it. Which is what he's always done, except with "Lolita"". When deciding on a subject for a film, there were many aspects that he looked for, and he always made films which would "appeal to every sort of viewer, whatever their expectation of film". According to his co-producer Jan Harlan, Kubrick mostly "wanted to make films about things that mattered, that not only had form, but substance". Kubrick believed that audiences quite often were attracted to "enigmas and allegories" and did not like films in which everything was spelled out clearly.