Jonathan Lewis is a well-known figure in the Oracle world, with more than twenty-five years of experience using the software. He has published three books about Oracle - the most recent being Oracle Core - and contributed to three others. He posts blog items related to Oracle on a regular basis and contributes to newsgroups, forums, and users group magazines and events around the world. Jonathan has been self-employed for most of his time in the IT industry. For the past twenty years, he has specialized in short-term assignments, typically of a design, review, or troubleshooting nature, often spending no more than two or three days on a client site to address problems. He runs seminars about using Oracle all over the world and has visited more than fifty countries (and more than a dozen US states) to talk about, or troubleshoot, Oracle systems.