This book contains the Proceedings of the second "Rencontres de l'Observatoire" devoted to Physics of Space: Growth Points and Problems, held at the Paris Observatory at Meudon, on January 10-14, 2000. The last quarter of the century has seen the vertiginous growth of space achievements and the exploration of much of the heliosphere with beautifully instrumented space probes. Even though the heliosphere is merely one particular cosmic environment, it is presently the only one accessible to in situ measurements and hence plays a unique role as a natural laboratory for physics and astrophysics. In this spirit, the conference highlighted recent achievements which have changed our view of the physics of space, with emphasis on the bridges between space plasma physics and other disciplines. The contributions include the physics of collisionless plasmas - in particular particle acceleration and dissipation, dusty plasmas, cosmic winds and jets, the environments of planetary bodies and pulsars, novel space detection techniques, and some landmarks of space physics history and possible futures.