A notable facet of the case of André Jolivet (1905-74) is the unusual amount and seriousness of attention that he devoted to writing articles on music theory. Generally, this was a reflective account which sought to explain both his compositional technique and his wider philosophy. What results is a rich theoretical repertoire to supplement the music. The objective of this chapter is thus twofold: firstly, to survey the most important concepts propounded in theoretic writings from the composer’s first mature period, chiefly those found in ‘André Jolivet, ou la magie expérimentale’; secondly, to pursue such music theory in action, with specific reference to Cinq danses rituelles (1939). Through this dual process, I aim to gauge relations between theory and practice, as well as those between Jolivet’s compositional approach to elucidating his music (‘poietic’ dimension) and receiver-based analytical or interpretative (‘esthesic’) approaches.