It is known that occasionally villages on the Italian island of Sicily must be evacuated due to the eruptions of Mount Etna. However, when the ash cloud from the Icelandic volcano under the Eyjafjallajökull glacier paralyzed half of European air traffic in 2010, it presented a completely new situation for Europe. While volcanic eruptions worldwide have always caused significant economic losses, Europe has so far been spared, with Vesuvius near Naples being the only active volcano on the mainland. This book provides an overview of volcanoes and volcanism in general, as well as the active volcanoes in Europe.