On behalf of the Program Committee, it is a great honor to welcome you to Lisbon, Portugal, to attend the 13th International Fuzzy Systems Association (IFSA) World Congress and the 6th European Society for Fuzzy Logic and Technology (EUSFLAT) Conference, IFSA–EUSFLAT 2009. It has been our pleasure as Program Committee Co-Chairs to help organize this meeting, prepare its technical program, and be involved in the making of these proceedings.

This would not be possible without help of many individuals, including the General Co-Chairs João Miguel Sousa and Uzay Kaymak, the Area Chairs and the Special Sessions Chairs, all the organizers and co-organizers of the 32 Special Sessions, members of program committees, technical committees and local organizing committees, and above all, the authors! Without their contribution, this year’s conference would not exist. We thank them all for their help and hope everyone will appreciate the result of their combined effort.

In these years deeply scarred by the largest global economic and financial crisis in over seven decades, IFSA–EUSFLAT 2009 still received a total of 473 submissions from over 53 countries from six continents. Each paper was reviewed by at least two reviewers and most papers had three or more reviews. Papers submitted for the 32 special sessions were peer-reviewed with the same criteria used for regular papers, and at least one reviewer was selected by an entity not involved in the organization of the special session. Based on the outcome of the review process and recommendations of the members of the program committees, 330 papers were accepted for inclusion in the conference program. We are very grateful to the numerous referees that helped us evaluate papers and build up the program. We have tried to propose homogeneous sessions as far as possible and to construct homogenous tracks of sessions with distinct topics.

The technical program brings together an outstanding diversity of papers that we are sure will make for an exciting conference. We hope you will enjoy the program as well as the location, and once again, we warmly welcome you to Lisbon!