Unlike The 400 Blows or Jules and Jim—the films that have done the most to secure François Truffaut's reputation—Shoot the Piano Player (1960) and The Wild Child (1970) are utterly inimitable. Both are showing this weekend at the Northwest Film Center, and the screenings are guaranteed to be this year's must-see double bill for Criterion-collecting cinephiles.

At first blush, the two films appear utterly different: Piano Player is a baroque exercise in reckless genre-hopping, while The Wild Child is a clinic of cinematic restraint. But a closer look at Truffaut's filmography reveals the kinship these two intensely idiosyncratic films share.

Fifty years ago this spring, Truffaut began an adaptation of Down There, the pulp novel by David Goodis, which eventually became Shoot the Piano Player. With this, his second film—and the follow-up to his critically lauded debut, 1959's The 400 Blows—Truffaut tried to translate Goodis' hardboiled prose into a kind of accidental musical, where gangsters only spoke of dames and the dames talked back. Critics and audiences shrugged their shoulders.

It was their loss: Never again would Truffaut indulge his whims quite so extravagantly. In reaction to Piano Player's critical drubbing, the feisty pup of the French New Wave scooted through the rest of the '60s with his tail between his legs, inching closer each time toward the bland "tradition of quality" he had attacked as a critic in the 1950s. Sure, there were admirable Jean Renoir homages (Jules and Jim) that kept him relevant, but there were also dull Hitchcock pastiches (Mississippi Mermaid) and awkward attempts to break big in English-speaking countries (Fahrenheit 451). By the end of the '60s, Truffaut was at another critical and commercial low; his back against the wall, he started The Wild Child, an ascetic retelling of a sort of noble savage's tale. Truffaut himself played a 19th century physician who takes a "wolf boy" into his home to study and civilize him. For the first time since Shoot the Piano Player, the director once again gave his obsessive streak free reign over his more self-conscious, legacy-pruning tendencies.