 Johnsonian scholar R. W. Chapman asked Powell to revise George Birkbeck Hill's edition of James Boswell's "Life of Samuel Johnson" in 1923.His revised edition was published in 1934 in four volumes and "thereafter, as for Johnson, the title was inseparable from his name".A fifth volume consisted of his edition of Boswell's "The Journal of a Tour to the Hebrides" after Boswell papers were discovered at Malahide Castle and Fettercairn House.