I think that at least one of the reasons is that the topic of many of his stories/novels is blurring the boundaries between the reality and non-reality (however

I think that at least one of the reasons is that the topic of many of his stories/novels is blurring the boundaries between the reality and non-reality (however that is defined in each novel). This is a recurring theme, with neither the reader nor the protagonist(s) being sure about things: * DADoES / Blade Runner: Who is an android/replicant and who is a human? * WCRIfYW / Total Recall: Which memories are real and which are implanted? * Ubik: Who is dead and who is alive? The filmmakers love this concept as it has many parallels with making films - see Inception and Matrix as examples.