Book excerpt: Welcome to the 6th Atlantic Web Intelligence Conference (AWIC 2009), to be held during September 9-11, 2009 in Prague, Czech Republic. The conference will be held at the Faculty of Mathematics and Physics of the Charles University, Prague. This building has a convenient location in the historical city center, in the area called Lesser Town close to local attractions like Charles Bridge and Prague Castle. The Atlantic Web Intelligence Conferences bring together scientists, engineers, computer users, and students to exchange and share their experiences, new ideas, and research results about all aspects (theory, applications and tools) of intelligent methods applied to Web based systems, and to discuss the practical challenges encountered and the solutions adopted. Previous AWIC events were held in Spain - 2003, Mexico - 2004, Poland - 2005, Israel - 2006 and France - 2007.