This paper was first published online by the Internet Society in December 2003 and is being re-published in ACM SIGCOMM Computer Communication Review because of its historic import. It was written at the urging of its primary editor, the late Barry Leiner. He felt that a factual rendering of the events and activities associated with the development of the early Internet would be a valuable contribution. The contributing authors did their best to incorporate only factual material into this document. There are sure to be many details that have not been captured in the body of the document but it remains one of the most accurate renderings of the early period of development available.