Volcanoes have captured the imagination and intrigue of the human civilization because of their unpredictable and destructive nature. Today, hundreds of volcanoes are being monitored for potential warning signs that precede an eruption including gas emissions, seismic tremors and ground deformation. We sit down with volcanologist Paul Ashwell to ask how the monitoring of  volcanoes has improved over the last half century and what challenges still lie ahead.    Primary reading discussed:  Forecasting Volcanic Eruptions