[1][4] In 1947, in recognition of her accomplishments, Diehl was made an Honorary Life Member of the Guild of Book Workers.

About finding bookbinding as a career, it was reported that she "grew so fond of books at Wellesley (...) that she decided to be one of those who give first editions a new lease on life by putting them in comfortable and at the same time decorative surroundings.

She had abandoned her hopes of becoming a teacher and devoted 5 years of apprentice work in England, France, and Belgium.

Diehl stated, ″it was only after five years of intensive study and practical work that I hung out my shingle.″[11] Diehl had bookbinding studios in various sequential locations in New York City during the first half of the twentieth century, moving uptown by degrees from Gramercy to Sutton Place, with interruptions during both World Wars.

Jeffrey Peachey, a book conservator, tool maker and historian [1] has published blog posts on one of Diehl's backing hammers.

[12][13] An example of a signed Diehl binding, the Sonnets of Michael Angelo Buonarroti as described in The Sun article cited, is available at The New York Public Library, Spencer Collection.

She organized over 500 workrooms and increased production by arranging for the cutting of bandages by electrically operated cutters.