It is our great pleasure to welcome you to the 10th International Conference on Aspect-Oriented Software Development (AOSD), for the first time in Brazil. AOSD is the premier forum for presentation of research results and experience reports on software modularity, with an emphasis on modular structures that cut across traditional abstraction boundaries. The annual AOSD series started in 2002 in Enschede (The Netherlands), followed by Boston, Massachusetts (USA) in 2003, Lancaster (UK) in 2004, Chicago, Illinois (USA) in 2005, Bonn (Germany) in 2006, Vancouver (Canada) in 2007, Brussels (Belgium) in 2008, Charlottesville, Virginia (USA) in 2009, Rennes and Saint-Malo (France) in 2010, and Porto de Galinhas in 2011. This year's conference continues the tradition of its successful predecessors with Research and Industry Tracks, which bring together leading researchers and practitioners working in such fields as software engineering, programming languages, systems, and others. Besides these tracks, this year we have the satisfaction of introducing the Modularity Visions Track, which aims to think about modularity for the future, and hosting an ACM SIGPLAN Student Research Competition. Finally, to celebrate AOSD's 10th birthday, we have a special Retrospective on Modularity session and an outstanding group of keynote and invited speakers. In this way we hope to continue broadening its scope with respect to software developments activities, and start broadening the scope with respect to other advanced modularization mechanisms beyond aspects.