Prepositions are still very difficult for me.

Why is "on" used instead of "in" in this sentence?

This library has the definitive collection of books on ancient Egypt.

I have no idea. Why is that?

Thanks for your help in advance.

  • Advice: some are logical, others need to be memorized. Books on [a subject] should be memorized.
    – Lambie
    Nov 28, 2018 at 16:07

1 Answer 1


This 'on' is basically short for 'on the subject of ...'

a collection of books on ancient Egypt = a collection of books on the subject of ancient Egypt

a collection of books in ancient Egypt = a collection of books which is physically located in Egypt

  • Also books on ancient Latin = books on the subject of ancient Latin, whereas books in ancient Latin = books written in the language of ancient Latin. Nov 28, 2018 at 15:14
  • @FumbleFingers also a good point.
    – kandyman
    Nov 28, 2018 at 15:14
  • There are other possible meanings for in in such contexts (books in the Industrial Revolution = books written / being circulated at that time) - but apart from the absolutely literal books on my bookshelf, I can't offhand think of any other possible meanings for on here. Nov 28, 2018 at 15:20
  • "'books in the Industrial Revolution" sounds a bit awkward to me. I would prefer "books of the Industrial Revolution" to mean books written during that period.
    – kandyman
    Nov 28, 2018 at 15:21
  • Well, Books in Medieval England gets an estimated 3500 hits in Google Books, and seems completely unambiguous and natural to me. But Books of Medieval England gets just 5 hits, and there are thousands of hits for Books of mathematics, which to me suggests that of occurs quite often with the sense on the subject of in this context. Nov 28, 2018 at 15:39

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