Fairbairn’s approach was largely from the angle of ego-development in relation to objects, while mine was predominantly from the angle of anxieties and their vicissitudes.
Klein explicitly delineates her theoretical differences from Fairbairn, identifying his object-relational, ego-developmental orientation as distinct from her own anxiety-centred approach, while conceding the clinical value of his schizoid phenomenology.
, Envy and Gratitude and Other Works 1946-1963, 1957thesis