The cytolytic large granular lymphoid cells first observed in his own blood by this author "as healthy control" in the late 1960s were referred to as "Burnet's immune surveillance cells". These cells killed autologous/allogeneic malignantly transformed cells close to immediately upon their contact. Healthy individuals and patients with cancers possessed these large granular lymphoid cells. Project site visitors of the NIH/NCI believed this phenomenon not to be an 'immune reaction', thus called it an " artifact". When the same large granular lymphoid cells were re-discovered elsewhere in 1975, first in mice, then in man, they were nominated to be "Natural Killer (NK) Cells". The identification of NK cells as being the same as the so-called "Burnet's immune surveillance cells" was never acknowledged in the published literature. This article uses documents preserved from the late-1960s and early 1970s to elaborate on the original circumstances of these two basically identical immunological observations.