This edited book contains a hitherto unpublished seminar held by the author in Milan, Italy in 1985. The seminar is preceded by a foreword by Kate White, of the Bowlby Centre, and by an introduction by the editor, Marco Bacciagaluppi. The introduction contains excerpts from unpublished correspondence between the author and the editor, carried out over a span of eight years, between 1982 and 1990. After the seminar there are the follow-ups of the three cases presented by Leopolda Pelizzaro, Ferruccio Osimo and Emilia Fumagalli, and a report by Germana Agnetti and Angelo Barbato, who gave hospitality to the author and his wife. This is followed by a contribution by Ferruccio Osimo on experiential dynamic psychotherapy, an application of attachment theory, with a long case study. At the end there are some concluding remarks by the editor.