Historically, yes, but current usage has relaxed. See [1]. Personally, I read the title to be a pun on "30 minutes or less", a phrase American pizzerias someti

Historically, yes, but current usage has relaxed. See [1]. Personally, I read the title to be a pun on "30 minutes or less", a phrase American pizzerias sometimes use to advertise guarantees about their delivery times. The book is promising to show you useful programs in "500 lines or less, guaranteed!". [1]: https://en.wikipedia.org/wiki/Fewer_vs._less https://en.wikipedia.org/wiki/Fewer_vs._less