This paper is intended to offer a foundation for comparison of the approaches of Wilfred Bion and Donald Winnicott. In particular, I try to plot the oscillation of Bion's clinical method from his early Group period at the Tavistock Clinic (up to around 1950) when he emphasized countertransference; his part-object interpretation method in the 1950s after his analysis with Klein when he and colleagues were experimenting with the psychoanalysis of people in psychotic states ; and then his return to his investigation of the intuitive approach to clinical data, around 1965-70.