The Paperchase was a game that used to exist in the Cambridge University Library (usually known as the UL). It worked like this: there was a initial clue, consisting of the name of a book and a page number. If you went and looked this up, having found the book's location via the catalogue, you found a slip of paper inserted at the specified page with another clue on it. This in turn led you to a further clue, and so on. As you got further through the Paperchase, the clues became harder, or led you to multiple books, so that the Paperchase split into multiple strands. There was a prize for completing the Paperchase: you were entitled to order a Paperchase scarf from a shop in Cambridge, but the real prize was the fun of solving the puzzles and riddles posed by the clues. The scarf, incidentally, consisted of stripes in the colours orange, green, blue, indigo and violet. That is, it was like the books in the UL: all the colours of the rainbow, but never re(a)d.
As far as I know, the Paperchase was set up in the mid or late 1970s, and I learned of it in 1981, during my time as an undergraduate. I completed it some time in 1982. I revisited it in 1985-86 and sometime around 1990, and repaired a few clues which had gone adrift. When I last checked it, sometime around 1999 or 2000, the first few clues had all gone, and I assume it has largely fallen into disrepair. Some of the clues while rely on the physical location or accessibility of parts of the library have become invalid as a result of changes in the layout of the UL.
Even if the Paperchase were still intact, it would almost certainly be much easier these days. In the early 1980s, only a small part of the UL's catalogues had been computerized, essentially books and serials published after 1976. The main catalogue consisted of large volumes into which slips of paper were pasted. There were two sets, one ordered by title and one by author. There were also numerous additional catalogues, for rarer material and for specialist collections. One of the pleasures of the Paperchase was discovering these catalogues and in some cases figuring out how they worked. You can find out more about the catalogues on the UL website. (If you look at this site, I would also recommend the charming account of marginalia and other crimes.)
So far as I am aware, there is no listing of all the books in the Paperchase on the web. The only reference I could find to it was this terse mention. When the Paperchase still existed, it would have been considered heresy to publish a list of all the clues and their solutions, but it seems appropriate (or at least, not inappropriate) to do so now.
The Clues of the UL Paperchase