EXCERPT Sándor Ferenczi’s Thalassa, written in 1924 but based on ideas dating from 1915–1920, is really a very peculiar book, described by the author himself as the result of a strictly inadmissible synthesis of ‘natural science and mental science’. Its subtitle positions it as ‘A Theory of Genitality’—that is, it presents an alternative account to Freud’s own of how polymorphic, disorganised libidinal drives become invested in the genital organs and thus aligned with the exigencies of organic reproduction. How do unformed blind inorganic forces disposed to perversity become integrated into and harnessed for the interests of the organism? What kind of libidinal investments and psychic processes correspond to this process of maturation?…