This open access book summarizes the findings of the VUELCO project a multidisciplinary and crossboundary research funded by the European Commissions 7th framework program. It comprises four broad topics1.ampampampnbspampampampnbspampampampnbspampampampnbsp The global significance of volcanic unrest2.ampampampnbspampampampnbspampampampnbspampampampnbsp Geophysical and geochemical fingerprints of unrest and precursory activity3.ampampampnbspampampampnbspampampampnbspampampampnbsp Magma dynamics leading to unrest phenomena4.ampampampnbspampampampnbspampampampnbspampampampnbsp Bridging the gap between science and decisionmakingVolcanic unrest is a complex multihazard phenomenon. The fact that unrest may or may not lead to an imminent eruption contributes significant uncertainty to shortterm volcanic hazard and risk assessment.ampampampnbsp Although it is reasonable to assume that all eruptions are associated with precursory activity of some sort the understanding of the causative links between subsurface processes resulting unrest signals and imminent eruption is incomplete.