These proceedings of an international conference held in Heidelberg, Germany, in September 2007, provide a comprehensive overview of the state-of-the-art of current research on high-mass star formation. Massive stars are very important. They synthesize heavy elements and shape the energy budget of the interstellar medium throughout their entire lifetime. Even so, the actual high-mass star-forming processes are still poorly understood. The associated problems are difficult and complex both from a theoretical and from an observational point of view. Therefore, the conference was specifically meant to foster discussions between theorists and observers so that new approaches and strategies to jointly tackle these problems can emerge.

More than 230 researchers gathered from around the globe. This volume contains contributions covering important questions in massive star formation research. These include: What are the initial conditions for massive star formation? What are the properties of massive young stellar objects and how do they evolve? How do massive (proto)stars accrete? Do they have accretion disks, and if so, what are their properties? How does clustering affect massive star formation? How important are turbulence and feedback processes like strong (ionizing) radiation fields or powerful jets and outflows? How does high-mass star formation affect the Galaxy as a whole? What can we infer for external galaxies with our local knowledge of massive star formation?

This book is suitable for researchers and graduate students interested in massive star formation and its associated physical processes. It contains 54 individual articles from distinguished international researchers. Summaries and transcripts of the two panel discussions are also included. It provides an up-to-date compendium of the current state of research and serves as a guideline for future research.