This text was prepared by psychologist and Jesuit priest Ignacio Martin-Baró for his ethics class in the psychology department at the Central American University, José Simeon Cañas, where he taught until his tragic death at the hands of the Salvadoran army on November 16, 1989. The text remained unpublished and circulated in typewritten pages, which included the integration of notes from his presentations in academic programs in different universities throughout Latin America. As part of the multiple tributes to the Jesuits on the 25th anniversary of the murders, the text was revised and enriched by a final section of references. It is published in accordance with the sequence that would give its author; Psychological Ethics, Values in Psycholgy, and Main Principles of Duty Be of the Psychological Activity.
Key words: ethics, psychology, subjectivity, ideology