Our present understanding of fundamental interactions is based on quantum field theory and general relativity.In spite of their respective striking successes,both frameworks suffer from conceptual difficulties. I will outline how a new approach - known as string theory - appears to solve those problems and could eventually provide an unified finite theory of all interactions..
General concepts that drive the design of a big collider experiment will be reviewed briefly. This seminar is an introduction to the lectures on "Particle Detectors"..