 Schilder wrote a series of articles in the thirties on the psychoanalysis of space, time and geometry, later subsumed into chapters of his 1942 book "Mind".Schilder is also considered one of the founding fathers of group therapy.He began using analytic and exploratory use of groups in both hospital and out-patient settings, as well as treating severely neurotic and mildly psychotic out-patients in small groups at Bellevue.