"This edition of the Concise Columbia Encyclopedia has entries specifically written and selected for the short form nature of a quick reference guide. Not just the first paragraph of a longer entry but an edited and shortened version that gets the key points across as a pocket reference should. Conversely it also packs in the breadth and detail needed to form a reliable learning and reference source. With nearly 17000 entries containing over a million words, from the main events of World War I to the Department of Homeland Security to biographic entries of pivotal historical figures, this comprehensive reference won't be found lacking."
You can buy this for $24.99 until May 31st at the developers website listed above.