The memoir I think about most as a craft achievement is The Liars' Club by Mary Karr, not because it's the most important memoir I've read but because it solves a specific technical problem: how do you narrate childhood experience in a way that preserves the child's limited understanding while giving the adult reader enough context to understand what was actually happening.

Karr does this through a combination of the child's voice (present tense, immediate, unable to fully interpret what she observes) and subtle adult framing (not intrusive commentary but selection and ordering that carries the adult's understanding). The child's account and the adult's structure coexist without the one undermining the other.

This is a problem specific to childhood memoir and Karr's solution is the best one I've seen. The child's experience is honored. The reader's understanding is served.