Socrates (http://en.wikipedia.org/wiki/Socrates and http://plato.stanford.edu/entries/socrates/) himself did not write any philosophical texts. Our knowledge of the man and his philosophy is based on writings by his students and contemporaries, particularly Plato’s dialogues, but also the writings of Aristotle, Xenophon and Aristophanes. As these are either the partisan philosophical texts of his supporters, or works of dramatic rather than historically accurate intent, it is difficult to find the ‘real’ Socrates (often referred to as the ‘Socratic problem’). In Plato’s Socratic Dialogues in particular, it is practically impossible to tell which of the views attributed to Socrates are actually his and which are those of Plato. We know that he was a kind of intellectual pugilist, arguing endlessly in the marketplace and irritating his contemporaries by tying them up in the knots of their own muddled thinking.
Vlastos’s 1991 book Socrates: Ironist and Moral Philosopher begins from the conviction that the strangeness of Socrates is the key to his philosophy. It is a marvellous book, in which no major aspect of Socrates’ career is overlooked. The rigour of his arguments, the depth of his moral commitment and understanding, his complex relationship to Athenian ethical traditions, his rational religion: all this comes to life in writing by Vlastos (http://en.wikipedia.org/wiki/Gregory_Vlastos) whose vigour and lucidity put the challenge of Socrates squarely before the reader.
For a quick introduction to this subject go to Taylor, C.C.W. (2001). Socrates: A Very Short Introduction. Oxford: Oxford University Press (http://www.amazon.co.uk/Socrates-Very-Short-Introduction-Introductions/dp/0192854127/ref=sr_1_1?ie=UTF8&qid=1387325408&sr=8-1&keywords=socrates+very+short+introduction)
An excellent 45 minute ‘In Our Time’ Radio 4 podcast of a programme originally broadcast in 2007 is available at http://www.bbc.co.uk/programmes/b007zp21 With Angie Hobbs, Associate Professor of Philosophy at Warwick University; David Sedley, Laurence Professor of Ancient Philosophy at Cambridge University; Paul Millett, Senior Lecturer in Classics at the University of Cambridge. First broadcast Thursday 27 Sep 2007.
For a more bracing dip into the subject reach for The Cambridge Companion to Socrates (2010, http://www.amazon.co.uk/Cambridge-Companion-Socrates-Companions-Philosophy/dp/0521541034/ref=tmm_pap_title_0?ie=UTF8&qid=1387325484&sr=8-1) edited by Donald R. Morrison.
For a lifetime of study and reflection on the thought and influence of Socrates follow the bibliographies in http://plato.stanford.edu/entries/socrates/.
500 pages in Cornell University Press
ISBN 978-0801497872
Socrates – irritating intellectual pugilist