Kristeva was a 'semiotician', but in this book sticks to interpreting Proust and his symbols. She makes some interesting connections, such as the sado-masochism of guilt as the central intensity behind complex emotions and therefore the hidden core of the 'lost time' Proust seeks to regain by memory; she finds enough evidence in old drafts and stories of Proust's to indicate that the famous madeleine has the Biblical overtone of Mary Magdalene and consequently confers an entire theological sense upon the entire novel. Kristeva also spends some time trying to clarify Proust's philosophic positions, feeling that his constant use of mixed metaphor makes Proust an early hermeneuticist, and that Proust's aesthetic theories placing emotional intensities, reached via art, at the center of reality can be traced back to Schoepenhaeur and a number of specific french disciples (the aesthete's will to art is the principle element of reality, to which all social and natural strata can be reduced to mere representation).
To an extent, Kristeva tries to demonstrate the error of Deleuze' book, which paints Proust as a Plastonist and a totally irrational hunter of emotion, by emphasizing the specificity of Proust's literal assertions and his decidedly German (and not Platonic) worldview; however, all these quibbles seem to indicate is that all these latter-day philosophers are mostly adding unoriginal reformulations to what Proust already said of himself in the final volume, Time Regained, where a thorough and explicit theory of aesthetics is delivered (and which suffices to explain Proust's own works). Indeed, all the interesting ideas in any of these commentaries seem already to be present in the original text -- are they, perhaps, written for those who don't want to read the novel itself?