Marjolaine Fournier and Jean-Jacques van Vlasselaer talk about two Concertos for orchestra: one by Béla Bartók and the other by Witold Lutosławski. They take a moment to explain the format of a concerto for orchestra (what do you mean, a concerto without a soloist?), and the dialog that develops within the orchestra performing it. Bartók and Lutosławski, who lived concurrently but in different contexts, composed two completely different and marvellous works.