Barcelona Asteroid Day 2015: Revisiting the Threat by Asteroid and Comet Impact

The general context in which was organized the Barcelona Asteroid Day 2015 workshop is introduced, together with a brief description of the contributions to this proceedings book. To promote the study of asteroids, comets and meteorites was one of the goals of the Barcelona event, an initiative born as part of the international Asteroid Day movement that tries to popularize the Tunguska event (on June 30th, 1908), the most energetic contemporary impact detected so far. This book compiles the contributions presented to this research workshop organized by the Institute of Space Sciences (IEEC-CSIC) at the UAB campus in Bellaterra, together with an outreach event led by astronaut Pedro Duque that conveyed the main issues to the general public. This workshop was coordinated with other initiatives around the world and intended to offer to the general public, and astronomy enthusiasts an environment for public awareness and open discussion. The event was intended to present the most recent science, to promote international cooperation and to raise the scientific interest of studying asteroids to the general public and the media.