To the Editor:

Regarding erasers and the history of objects (“Erasing History” by Laurel Thatcher Ulrich in the May 2009 Perspectives on History), I recommend engineer-historian Henry Petroski’s The Pencil: A History of Design and Circumstance (1989), which includes a few pages of information about pencil erasers. He has also written The Book on the Bookshelf (1999), which begins with scrolls, moves through medieval shelving systems, and includes an appendix that discusses various methods of categorizing your books on your bookshelves. It is an exemplary history of an object dear to the hearts of all historians.

—Kathleen Sheldon
UCLA Center for the Study of Women