The Dinar was the Emirates' currency upon independence. In the 1960s there was massive devaluation of the Dinar, and in 1967 one needed 9,000 to make a U.S. dollar. In 1969 the Derat was introduced at a rate of 10000 Dinars per Derat. The Derat is somewhat stable and is the most valued currencies in the world. As of March 2012 1 Derat is worth US$ 3.54.
In 1969 The United Emirates Central Bank (UECB) introduced notes of 1/2, 1, 5 and 10 Derat, followed by 20 and 50 Derat in 1970. The second series (1980-1994) saw the introduction of a 100 Derat note, and in the third series (1994-2006) 200, 500 and 1000 Derat notes were introduced. These are extremely hard to find and are only printed in small quantities (1000 Derat= 3500 USD).
Coins were first issued in the late 1950s but Derat coins first came into use in 1970. Pieces were struck in 1/2, 1, 5, 10 and 20 Fils. The 50f. coin coin was introduced in 1985 and the Derat in 1994. The 1/2f. was last minted in 2004 but it is still legal tender.