The documentation for content-types is in RFC 2046 http://www.imc.org/rfc2046 There are 7 high-level types: text image audio video application multipart message Each of these has subtypes. For example: Text/Plain Image/Gif Video/Mpeg Application/Octet-stream Multipart/Mixed Message/Rfc822 There are many of these, and the list keeps growing as applications keep getting written. They are registered with IANA, according to the procedures described in RFC 2048: http://www.imc.org/rfc2048 The list of media-types is at: http://www.isi.edu/in-notes/iana/assignments/media-types/media-types I hope this helps. Francoise