Prom 52 offered a fascinating musical journey with French organist Thierry Escaich, who juxtaposed the organ music of J.S. Bach with responses to it by Mendelssohn and Brahms, as well his own improvisations on themes by Bach.
Escaich is part of the grand French tradition of organ improvisation which dates back to the 19th century, and he succeeded another great French composer and organist at St Etienne du Mont, Maurice Duruflé. Escaich calls the art of improvisation “composition in real time” and in an interview for BBC Radio 3 explained that he can often improvise for 20 minutes during a Catholic mass “in Bach style, in Romantic style”. In discussing Mendelssohn, whose Organ Sonata in A major featured in this programme, Escaich described this music as Bach “with a little more romanticism”, and explained that in his own improvisations he adds his own personality to the music of Bach, while honouring Bach’s themes, textures and idioms. The end result is music which shines a new light on Bach’s original, while demonstrating the exciting range of possibilities offered by this genre.
Read my full review here
The Cross-Eyed Pianist 
I wholeheartedly agree with everything you say. Prom 52 with Thierry Eiscach was a stunning musical and sonic experience and in the context of his Études and Improvisations, Bach and Mendelssohn sounded avant-garde, even now, suspended in the ether of all time. We were overwhelmed with joy. The only other time we heard a comparable feast of organistic improvisation, delicacy and genius was the Prom with Wayne Marshall playing Messiaen, Duruflé and Loriot ending with Wayne Matshall’s homage to Olivier Messiaen on a theme of Duke Ellington – my mind is flooded with enveloping sound.