In this introduction, recent progress in the study of the evolution, transfer and release of magmas and volcanic gases is briefly reviewed, based on discussions at the MAG2007 international conference held in Taipei, Taiwan, in April 2007. The meeting pooled the diverse expertise of igneous and volcanic gas geochemists. This special issue, which presents six case studies covering a range of topics from variations in mantle source compositions to the nature of volcanic degassing, reflects that diversity.