The difficulty in summarizing La Modification, like Butor's other novels, comes not from an excess or an absence of "content" as such, but from the insistent dualism, the simultaneous presence of inner and outer worlds.

The basic analogy that governs the novel is the funambulist figure of the motionless traveler. (p. 174)

[The passenger] Léon Delmont sees simultaneously the reflection of his own face [in the train window] and, juxtaposed, the familiar scenery where he loses himself, through which other trains run, crossing his, transformed into the trains he has taken on other trips at other times.

The idea of a glass separating the individual from experience, the consciousness from act, has become a commonplace of the modern scene. Butor seeks not to give in to either side of an antinomy between the distortions that might be induced from the surface of the glass itself (Robbe-Grillet) and the...