This book updates the Historical Dictionary of the United Nations published in 2007, successor to the original 1995 edition. (A paperback version, The A to Z of the United Nations, came out in 2009). At nearly 800 pages and over 1,000 entries, it is a much-needed and welcome revision. The author, a former member of the UN Secretariat, has fine-tuned the contents, deleting entries and refreshing and adding others. The entries are brief, typically no more than a page, and, as is invariably the case with encyclopedic works, deciding what to include and leave out is a matter of editorial judgment. The book follows the same format as others in the "Historical Dictionary" series, with a revised introduction, chronology, and bibliography supplemented by several appendixes. Comparable works include The Concise Encyclopedia of the United Nations (Martinus Nijhoff, 2010) and Encyclopedia of the United Nations (Facts on File, 2002). The four-volume Encyclopedia of the United Nations and International Agreements (Routledge, 2003), albeit dated, remains primus inter pares.Summing Up: Recommended. Lower-division undergraduates through faculty.