Neal Stephenson writes speculative fiction. In his books, he explores subjects such as mathematics, cryptography, linguistics, philosophy, currency, and the history of science.
Writing novels is hard, and requires vast, unbroken slabs of time. Four quiet hours is a resource that I can put to good use. Two slabs of time, each two hours long, might add up to the same four hours, but are not nearly as productive as an unbroken four. If I know that I am going to be interrupted, I can’t concentrate, and if I suspect that I might be interrupted, I can’t do anything at all. Likewise, several consecutive days with four-hour time-slabs in them give me a stretch of time in which I can write a decent book chapter, but the same number of hours spread out across a few weeks, with interruptions in between them, are nearly useless.
— Neal Stephenson, Why I am a bad correspondent