The book, based on Apted's voluminous memoirs and letters, is being organized and edited by Robert S. Playfair '36, and is expected to appear this spring. "Within and Without the Gates of Harvard ...

The Double Playfair is an extension of the Playfair to use two separate keys and to encipher each pair of letters twice. The German police made the mistake in late 1941 of switching from the ...

So, in 1786, he published The Commercial and Political Atlas, a book that introduced the first bar graph and line charts. Instead of dry tables, Playfair used these visual tools to show trade data ...