Too much information?

Ransome Boats, a photo by The original SimonB on Flickr.

So when, exactly, does an interest tip over to become an obsession?

I am currently reading Arthur Ransome's "Racundra's First Cruise", a tale of sailing on the Baltic just after the First World War. It is a book I've been wanting to read for some 30+ years since I first noticed it listed in the front of one of the Swallows and Amazons series. Not continually I should add, interest has waxed and waned over that time, and even now it has sat on the shelf for over four months before I could bring myself to make a start. Anticipation being part of the pleasure of any book for me. But, a quick count up reveals I now have 24 books by or about Ransome with a couple more sat on my Amazon wish list... (Oh, and the Swallows and Amazons film on DVD plus audio versions of 8 books, a radio play and a documentary and have also been aboard three of his yachts - as pictured above).

That's not the highest tally for any one author (f'rinstance Terry Pratchett has reached number 38 in the Discworld series plus there are all the other non-Discworld books, spin-offs, graphic novel versions etc) but I'm not sure that counts as obsessive. Just following the works of a good author. I'm thinking more about what level of interest goes beyond this.

I used to think I was well up on Human Origins, with 8 or 9 books on the subject (and one or two more I'd borrowed from the library) but that's really nothing to the Space Programme (15) or Maps (20+) or Transport in general (over 50 - heck I seem to have accumulated at least 20 books by Top Gear presenters or spun-off from the magazine). But is this normal behaviour?

OK, I know that compared to much of the population even owning one book doesn't count as normal, but among those who do have a shelf or two?

Whatver the answer, I'm not going to stop now, even if I do need to get some books on carpentry and work out the best way to knock up some more shelves...