This book is based on the NATO Advanced Research Workshop on Structures of Com munication and Intelligent Help for Hypermedia Courseware, which was held at Espinho, Portugal, April 19-24, 1990. The texts included here should not be regarded as untouched proceedings of this meeting, but as the result of the reflections which took place there and which led the authors to revise their texts in that light. The Espinho ARW was itself to some extent the continuation of the ARW on Designing Hypermedia/Hypertext for Learning, held in Germany in 1989 (D. H. Jonassen, H. Mandl (eds.): Designing...