You are cordially invited to participate in the twenty-eighth Annual Conference of the North American Chapter of the International Group for the Psychology of Mathematics Education (PME-NA), to be held in Mérida, Yucatán in Mexico on November 9 to 12, 2006. The conference is sponsored by the Universidad Pedagógica Nacional (National Pedagogical University). The purpose of the meeting is to provide a forum for scholarly discussion of central and current issues in mathematics education and for the exchange of research information on the psychology of mathematics education. English is the official language of the conference.