This non-technical biography of Jacobus Cornelius Kapteyn (1851-1922) presents to the general reader the scientific life of the astronomer who pioneered the studies of the structure of the Milky Way Galaxy. In telling Kapteyn's story the author weaves in astronomy basics and uses modern astronomical images to show the developments of astronomical research from Kapteyn's times to the present. In particular the study of the distribution of stars in space has now culminated with spectacular new insights coming from the astrometric satellite GAIA, which is receiving much public attention today.

The biography shows how Kapteyn's ideas influenced prominent astronomers worldwide. He is prominent as designer of the Kapteyn Universe, the alternative to the large system found by Harlow Shapley. He is the discoverer of Kapteyn's Star, still the second fastest moving star in the sky, which is now one of the nearest stars with a planet in the habitable zone.

This fascinating hybridof astronomy history and popular astronomy tells the story of the astronomy professor without an observatory who founded the first astronomical laboratory specializing in measuring photographic plates exposed elsewhere. Kapteyn took astronomy out of cataloguing stars to measuring distances and velocities in order to study their spatial distribution, systematic motions (Kapteyn's Star Streams) and the equilibrium between their gravity and motions. His legacy includes, in addition to the first application of Galactic structure and dynamics, Jan Hendrik Oort, the famous astronomer from Leiden, who as a student was so impressed by Kapteyn's lectures that he decided to become an astronomer.

Autorentext
Pieter C. van der Kruit is emeritus Jacobus C. Kapteyn Distinguished Professor of Astronomy at the Kapteyn Astronomical Institute of the University of Groningen, the Netherlands. He obtained his PhD in astronomy from Leiden University in 1971 under Jan Hendrik Oort. He held a prestigious Carnegie postdoctoral Fellowship at the Mount Wilson and Palomar Observatories in Pasadena, California, before moving to the University of Groningen in 1975. He has held visiting positions at various institutions, including the Mount Stromlo Observatory in Canberra, Australia; the Institute of Astronomy in Cambridge, UK; the Space Telescope Science Institute in Baltimore, USA; the European Southern Observatory in Santiago, Chile, the Instituto de Astrofisica de Canarias in Tenerife, Spain, and the Carnegie Observatories in Pasadena, California. His research concerns structure and dynamics of disks in galaxies. He has published over 160 papers, more than half as lead or sole author, contributed substantially to over 20 more, and authored or edited eight books.
In Groningen he taught introductory astronomy and advanced level courses on structure and dynamics of galaxies for many years, the latter also at a Saas-Fee winter school in Switzerland and in university curricula in Porto, Portugal, in Santiago, Chile and in Beijing, China. He is a former director of the Kapteyn Astronomical Institute and has been a member and often chairman of numerous national and international boards and committees, notably President of Council of the European Southern Observatory and chairman of the Board for the Atacama Large Millimeter Array ALMA. In 2006 he received a Royal Decoration as Knight in the Order of the Dutch Lion.

Inhalt
Introduction.- Boarding School and University.- Astronomy Around 1875.- Astronomer and Professor.- Almost Half a Million Stars.- Laboratory and Statistical Astronomy.- Star Streams.- In the mean time in Groningen.- Mount Wilson.- Statistics and other matters.- First Attempt: the Kapetyn Universe.- Coda.