The conversation of Jesus with Nicodemus belongs not only to the theologically important but also to the exegetically controversial pericopes of the fourth gospel. Scholars have named it -"Summe des Evangeliums"- and -"Evangelium en miniature"- (cf. Jurgen Becker). Jn. 2,23-3,36, structured as a diptych of parallel and complementary scenes (2,23-3,21 & 3,22-36), each having a similar tripartite structure, contains the synthesis of the fourth evangelist's Christology and soteriology and serves as a key to understand the scheme of the whole gospel. Using the current tools of literary and narrative criticism (characterisation, chiasmus, double entendre, dualism, irony, misunderstanding, parallelism, plot, symbolism, etc.), the author examines minutely the network of Jn. 1,19-4,54, subjects Jn. 3 to a thorough exegesis, defends the integrity and unity of Jn. 3 and analyses the heart beat of the gospel, "viz." its double and parallel Christology of the Son of Man and Son of God, which complement each other. Being at home in French and German besides English, through a wide consideration of literature and multi-disciplinary methodology, he contributes substantially to the understanding of a central text of the fourth gospel."