The concept of Stellar Populations has played a fundamental role in astronomy in the last few decades. It was introduced by Walter Baade after he was able to resolve the Andromeda Nebula and its companions into stars when he used red-sensitive plates and realised that there were two fundamentally different Herzsprung-Russell diagrams in our and these nearby galaxies (common stars in the solar neighborhood versus globular clusters). This result was published in two papers in 1944 in volume 100 of the Astrophysical Journal. Subsequent research gave the concept a much firmer basis and at the...

The concept of Stellar Populations has played a fundamental role in astronomy in the last few decades. It was introduced by Walter Baade after he was able to resolve the Andromeda Nebula and its companions into stars when he used red-sensitive plates and realised that there were two fundamentally different Herzsprung-Russell diagrams in our and these nearby galaxies (common stars in the solar neighborhood versus globular clusters). This result was published in two papers in 1944 in volume 100 of the Astrophysical Journal. Subsequent research gave the concept a much firmer basis and at the...

Jacobus Cornelius Kapteyn (1851-1922) of the University of Groningen was one of the foremost astronomers of his time, resulting in a leading role internationally of Dutch astronomy throughout the twentieth century. This volume, which is the proceedings of a special legacy' symposium at the celebration of the 385th anniversary of the University of Groningen, addresses Kapteyn's influence on the development of modern astronomy through studies of his pioneering work on statistical astronomy and the Structure of the Sidereal System, and his leadership in establishing international collaborations,...