Neither the formation process of "The First Stars" nor their existence in the present universe is known with any certainty. The authors of this volume address all open questions presenting an abundance of interesting data at the same time as giving an exhaustive overview of our present-day knowledge. This covers research from spectroscopic observations, stellar evolution, nucleosynthesis, structure and galaxy formation. The contributions shed new light on past views, often questioning traditional interpretations. Dealing with problems at the crossroads of cosmology, star formation and galactochemical evolution in stars, the book addresses researchers graduate students in astrophysics, nuclear physics and astrochemistry.