Ten years after writing ‘Les Corps glorieux’ Olivier Messiaen developed a plan to compose a Book of Rhythmic Studies for the organ. This resulted in two distinct works of which ‘Livre d’orgue’ proved to be an anthology representative of his compositional thinking at the time. It runs the gamut of rhythms, tone colors and sonorities, ranging from extreme delicacy to the most powerful vehemence, and includes new modes, complex Hindu rhythms, and an aviary of birdsong. The test piece ‘Verset pour la fete de la Dedicace’ offers a more serene vision in its own essay in birdsong. Tom Winpenny is Assistant Master of the Music at St. Alban’s Cathedral, where he accompanies the daily choral services and directs the Abbey Girls’ Choir. Previously, he served as sub-organist at St. Paul’s Cathedral, London. He is also musical director of the London Pro Arte Choir. Winpenny has broadcast frequently on BBC Radio and featured on American Public Media’s pipedreams. He was organ scholar at King’s College, Cambridge, graduating with a music degree, and twice accompanying the festival of Nine Lessons and Carols, broadcast worldwide.