What books did Socrates write?

Socrates (greek Σωκράτης) did not write any books. He believed that the "revolution" of the written speech (at that time writting was considered a revolution, remember that Homer Iliad and Odyssey were preserved via oral tradition and only at 800 BC were they written down) was something bad and he urged young ones refrain from it, because he thought that written speech was much less personal and much more superficial than the oral speech. That is why he went everyday to the ancient Market (Αγορά - Agora) to talk to young people. What we know about Socrates we know from what other philosophers have written about him and his sayings (mainly Plato).