Books don't crash

"WN: How does writing compare to coding?

Hertzfeld: I would say the key difference is the rigor. Writing you can get away with being sloppy and your book doesn't crash. It's not quite as objective. The way they are similar: They are infinitely refineable. The more you work on it, the better you can make it -- in both code and prose. And of course, there's the similarity that in both of them, it's just me sitting in front of the keyboard just thinking about typing."

From an interview with former Mac programmer Andy Hertzfeld, now turned author.