Locating the book or document you want traditionally goes something like this:
you get a reference (from a footnote or a lecturer, or a subject search); you search the library catalogue to see if and where we have it; and if it's a book we don't have, you search the Borrow Direct catalogues to see if you can request it from one of those libraries - and if there are any steps here that you're not sure about, you ask us, OK?
If you can't find what you want, you fill out a document delivery request form, and we'll see if we can get it from another library for you. Basically, we use catalogues and indexes to verify that the item exists, then work out where to get it from.
It works pretty well most of the time.
But sometimes we resort to a "speculative request" if we can't find the item you want in conventional indexing tools - maybe because it pre-dates online tools, maybe because it was never formally published, maybe because you have an incomplete reference, maybe because it's an unreported case from a lower court. A speculative request involves us making an educated guess about which library might have the item you want, and it relies on the staff at that library knowing their collection well enough to locate it (if they have it). We recently used this method to get a copy of an early NZ bill - not surprisingly we got it from the Parliamentary Library. Fortunately someone kept the bill, even though parliament threw it out.
So if there's something you want, just ask. Even if you don't have all the details.