After the end of the 4th edition of ISTA, held in Holstebro in 1986 between September 7th to 21st, Jean-Marie Pradier, member of the scientific staff since the first ISTA edition, reports on the activities which took place in the session. The report, accessible at Odin Teatret Archives, presents in depth the theme of the session, the characteristics of the research and the organisation of the congress.