Sources  Kevin Jon Davies Dirk Maggs James Thrift and Jim Lynn have all posted messages in the forums at the Douglas Adams Continuum When they talk about things to do with Douglas Adams that they are directly involved in then they are a  primary sources as long as you believe it is them posting the messages  Biographies such as the ones by Nick Webb and MJ Simpson are secondary source material  The biographers generally have access to better primary source material than most people and sometime reproduce parts like the original synopsis for the radio series in Gaimans book