Short answers, pulled from the story.
Charles Rosen is best known for The Classical Style, his 1971 book analyzing the music of Haydn, Mozart, and Beethoven, which won the National Book Award in Arts and Letters. He was also a widely respected concert pianist who recorded works by Stravinsky, Boulez, and Elliott Carter at the composers' own invitation.
Rosen studied piano with Moriz Rosenthal and Rosenthal's wife, Hedwig Kanner, after leaving the Juilliard School at age eleven. Rosenthal, born in 1862, had been a student of Franz Liszt, giving Rosen a direct pedagogical link to nineteenth-century performance practice.
Rosen held a PhD in French literature from Princeton University, completed in 1951 with a dissertation on the poetry of Jean de La Fontaine. He never formally studied musicology, though he later held teaching positions in music at Stony Brook University, the University of Chicago, Harvard, Oxford, and the Royal Northern College of Music.
Rosen won the National Book Award for The Classical Style and the Otto Kinkeldey Award from the American Musicological Society for The Romantic Generation in 1996. He received the Edison Prize in the Netherlands for his recording of Boulez's complete piano works, Grammy Award nominations for his Beethoven recordings, and a National Humanities Medal presented by President Obama on the 13th of February, 2012.
Rosen began writing to replace sleeve notes he found objectionable on his own recordings. His 1960 Chopin release included a note describing a late nocturne as "staggering drunken with the odour of flowers"; dissatisfied with that prose, he started writing the notes himself, which led to articles and eventually to his first book.
Rosen argued that Beethoven belonged squarely within the Classical tradition from which he emerged, not as a forerunner of Romanticism. He made the case in The Classical Style that the Romantic movement in music grew from a rejection of the principles on which Beethoven composed, and that the Romantics' veneration for Beethoven was in some ways an impediment to their best work.