Audio Forum is the largest tape producer in the country, and was one of the pioneers in the mid-seventies. They are perhaps best known for their wide range of language tapes. Many different learning levels are catered to, and they offer some fairly esoteric languages. However, they also have many self-help, cultural, religious and philosophical tapes in quite a variety of categories from many well known names, Alan Watts, Idries Shah, Doris Lessing, and Laurens Van Der Post on one page alone. You can get the Bible from them in eleven languages. They are also the US agents for the BBC archive series. If you are looking for serious audio presentation of ideas and theories, this is the place to look.