The Russian-born novelist's writing habits were famously peculiar. Beginning in 1950, he composed first drafts in pencil on ruled index cards, which he stored in long file boxes. Since Nabokov claimed, he pictured an entire novel in complete form before he began writing it, this method allowed him to compose passages out of sequence, in whatever order he pleased...
Mason Currey, Daily Rituals: How Artists Work
vladimir-nabokov, writing-process