After his death she edited the third edition of the Principles.
She thus became the obvious choice to edit the next edition of the book, the 14th, which was published in 1968.
A revised edition, edited and updated by the author, was released in 1978.
The second edition, also edited by Apel, was published in 1969.
From the start, the firm has seen its role as being to produce editions edited to exemplary standards.
He also edited the fourth edition of Roget's, published in 1977.
He edited the first major scholarly edition of Pushkin's works in 1855.
In 1900 he edited an edition of Shelley's works.
He edited with distinguished ability the last edition of "South on the Bones."
He also edited the definitive edition of Churchill's speeches, in eight volumes.