In addition to being fascinating astrophysical laboratories in their own right, Herbig-Haro flows have in recent years emerged as key phenomena in our attempts to understand the complex and violent processes that govern the birth of low mass stars. This work provides an overview of the major advances which the study of Herbig-Haro jets has enjoyed since 1995. On the observational side, Hubble Space Telescope images have revealed the intricate details of the shock structures in these supersonic flows, millimetre interferometry and infrared imaging can now probe the detailed structure of the molecular component of deeply embedded jets, and sub-millimetre and radio continuum maps now enable us to study the near environment of the optically invisible driving sources of jets. On the theoretical side, detailed numerical and analytical magnetohydrodynamic models have reached a level of sophistication that allows realistic comparison with observations and insights into the jet formation mechanisms. Similarly detailed observational and theoretical studies of the disks and winds of T Tauri stars are now gradually being linked to the Herbig-Haro flows, providing a first glimpse of how stars can be born by both accreting and ejecting infalling material.

Herbig-Haro objects were discovered 50 years ago, and during this half century they have developed from being mysterious small nebulae to be coming an important phenomenon in star formation. Indeed, HH flows are now recognized not only as fascinating astrophysical laboratories involving shock physics and chemistry, hydrodynamics and radiation processes, but it has gradually been realized that HH flows hold essential clues to the birth and early evolution of low mass stars. IAU Symposium No. 182 on Herbig-Haro Flows and the Birth of Low Mass Stars were held from January 20 to 24, 1997 in Chamonix in the french alps. A total of 178 researchers from 26 countries met to discuss our present level of understanding of Herbig-Haro flows and their relation to disk accretion events and T Tauri winds and other outflow phenomena like molecular outflows, embedded molecular hydrogen flows and radio jets. The present book contains the manuscripts from the oral contributions of the symposium. The poster papers were printed in a separate volume Low Mass Star Formation - from Infall to Outflow, edited by Fabien Malbet and Alain Castets, which was distributed at the beginning of the meeting. Together these two books document the vigorous state and the scientific appeal which research into Herbig-Haro flows and related issues in star formation enjoys today, observationally as well as theoretically."