The primary source of information on coin denominations, their origins and history, is: Dictionary of Numismatic Names by Albert R. Frey. This book, over 300 pages, was originally published in 1917 by the American Numismatic Society of New York. It was reprinted in 1947, and reprinted again in 1974 with a 94 page glossary of numismatic terms in English, French, German, Italian and Swedish, compiled by Mark M. Salton. However, having been compiled nearly 100 years ago, many coin denominations are missing --- all those created in the past hundred years. In addition, Frey didn't consider paper money denominations. There are quite a few denominations used today on paper money which never existed as a coin. Another useful though older source is Hazlitt's Coinage of the European Continent. And as mentioned above, there is Adrian Room's "Dictionary of Coin Names" published in 1987. The focus of this work is the etymology or origin of the word rather than a history of the coin. The book runs 250 pages and includes an appendix of coin families -- that is, denominations which are related, usually in their origin. An example of this woud be the "Crown" family, which includes Corona, Coronato, Couronne, Korona, Koruna, Krona, Krone and Kroon. These all derive from the Latin for "crown". Another would be the "shield" family -- Ecu, Escudo, Escudillo, Scudino and Scudo. Or the "lion" group -- Leeuw, Leone, Leopard, Leu and Lev. An interesting origin is the Lek denomination of Albania. This comes from the Albanian name for Alexander the Great.