As one of the three copy-right libraries in the UK, the Bodleian Library holds enormous collections of printed and manuscript materials. You can check items on the online catalogue before you plan your trip. You will need to register for a reader’s card (there’s a form you can fill out in advance here) and, as sometimes the books can take more than a day to arrive from the stacks, it is often best to order the books you want at least a day before your visit. I’ve heard a rumour that some of the books are kept in an old salt-mine in the middle of nowhere. That’s probably a lie but it might explain why some items take so long to arrive.
If you’re planning to consult some very old books, or material that is considered fragile (like some periodicals) you’ll need to order them into one of the special collections reading room in the Weston Library. The Weston Library is very pretty but the system is a bit confusing at first. There’s an excellent guide to using Special Collections in Oxford here.
Since the Bodleian is right in the centre of Oxford, it’s very easy – though not cheap – to find a place for tea and cake after your grueling research session. There is a little tearoom in the Weston Library but it is almost always packed. My advice is to head to The Vaults & Garden Cafe or the Covered Market for lunch.