Harrison Salisbury was the first American newsman permitted behind the enemy lines in North Vietnam; his visit lasted from December 23, 1966 to January 7, 1967 and in itself indicated to him a willingness on the part of Hanoi to investigate the possibility of negotiation. A trained observer with years of experience in Communist countries behind him, Salisbury saw and assessed the results of American bombing, the determination and resilience of the North Vietnamese who believe they are fighting a sacred war for independence and are prepared to fight for twenty years--""How many years the war goes on depends on you,"" Premier Pham Van Dong told him. Salisbury came back with a new concept of the relative independence of Hanoi from Peking and Moscow, with an idea of the relation between the Viet Cong and Hanoi, and with four pre-conference points required by Hanoi for negotiation proceedings which ""should not be considered conditions...they are real to us"" (Premier Van Dong). ""To my mind the arguments run strongly toward an effort to negotiate,"" he states. His eye witness account, already somewhat dated (re bombing strategy, for example), affords an accessible view of the enemy to the general public who, if they have not read it in the New York Times, can read it here, in an expanded version.