I would check out Philosophy Bites, which is a podcast interviewing active research philosophers in 15-20 minutes about their topics.<p><a href="http:&#x2F;&#x2F;www.philosophybites.com&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.philosophybites.com&#x2F;</a><p>Check out Stanford Encyclopedia of Philosophy, which is free and edited by active research philosophers on pretty much every major topic and figure.<p><a href="http:&#x2F;&#x2F;plato.stanford.edu&#x2F;" rel="nofollow">http:&#x2F;&#x2F;plato.stanford.edu&#x2F;</a><p>Naming and Necessity by Kripke is about reference and the causal theory of reference, but it assume a decent amount (in case that is what you were asking for specifically).<p>The Very Short Introductions series have some really good booklets if you want quick ways to jump into a topic.<p>A few other books:<p>B Russell The Problems of Philosophy. OUP (dated, but a classic general introduction)<p>Simon Blackburn Think. Oxford (nice general introduction)<p>Tim Crane The Mechanical Mind. Penguin (Nice introduction to phil of mind)<p>A J Ayer Language, Truth, and Logic. Penguin (dated, but a classic)<p>D Hume Enquiries<p>T Kuhn The Structure of Scientific Revolutions. Univ of Chicago Press