His specialisms included Victorian melodrama and the theatre of Henry Irving, W. S. Gilbert, Oscar Wilde and Arthur Wing Pinero.
Rowell lectured in drama at Bristol University from around 1950, joining a fledgling department that consisted of Glynne Wickham, George W. Brandt and John Lavender.
The department can also lay claim to a piece of theatrical history; they hosted the premiere of Harold Pinter's first play, The Room, in May 1957, performed in that former squash court of a theatre, The Drama Studio.
He published extensively upon his specialist area, as the bibliography below attests; of particular worth to students and scholars are his collections of dramatic texts, each meticulously contextualised and introduced.
As well as collections of Arthur Wing Pinero and W. S. Gilbert's works, he compiled many rare and important plays and critical articles.