Do I need to read lots of philosophy books before my Oxford interview?

In short, no. The Oxford philosophy course is designed so that you don't need lots of prior knowledge about different philosophers or the field in general - if you didn't take Philosophy and Ethics at A-level, it's definitely not a huge disadvantage. In fact, sometimes being new to philosophy can make it easier to think on your feet during interviews, because you're not stuck trying to remember the name of some specific argument or philosopher when answering questions!That said, having one or two books under your belt definitely can't hurt, and it can be useful to fall back on something you've read if you find yourself not quite knowing how to approach a question. Simon Blackburn's 'Think' is on a lot of reading lists for prospective philosophy students, and for good reason: it offers a really useful overview of a lot of key philosophical issues. Some basic knowledge of formal logic can also be really helpful, as a lot of questions on the TSA and in interviews revolve around logic puzzles, e.g. a tutor might ask you to consider whether the argument "It is raining. It is not raining. Therefore, the Pope is green." is valid. To help with these kinds of puzzles, I would highly recommend reading the first chapters of Volker Halbach's 'Logic Manual'. It can be tricky in places, but given that it's the set text for first year logic, getting to grips with the basic concepts before interview should give you a very definite head-start!