This is a compendium of the projects by Unit 20 students of the Bartlett School of Architecture, University College London, one of the world's top and most experimental architecture schools. The unit is directed by Salvador Perez Arroyo and Marcos Cruz, who have been working together on it for three years. The projects, which are published with the collaboration of the architecture school of the Universidad Politecnica of Valencia, are of great experimental value and have been developed with very precise models and large-scale computer drawings. Each project is explained at length and in detail. The book covers three years of work on themes such as: growth, micro-machines, prostheses and nanotechnology. The projects have won numerous awards from the university. The book reflects the notable influence of Peter Cook, Director of the Barlett School and author of the introduction, and of the Archigram philosophy translated into our contemporary language.