Swetlana Hubrig studied astronomy at St. Petersburg university and started her professional work at the Zentralinstitut für Astrophysik in Potsdam, where she obtained her PhD in 1989. During the 1990s, she held several positions and grants, both at the Potsdam university and the Astrophysikalisches Institut Potsdam (AIP), habilitating at the university in 2000. From 2001, she worked as operations staff astronomer for the European Southern Observatory on the Very Large Telescope, until she moved back to the Leibniz-Institut für Astrophysik Potsdam to become the head of the stellar physics and stellar activity department in 2009. Swetlana is working on many aspects of the magnetism in stars and is an expert in high resolution spectroscopy.

Markus Schöller studied physics at the universities in Köln and Bonn, where he obtained his PhD in 1996, working at the Max-Planck-Institut für Radioastronomie. Markus joined the European Southern Observatory in 1997, where he mainly works on the Very Large Telescope Interferometer and its scientific instruments. His main science interests are binarity and the magnetism in stars and he specializes in high angular resolution techniques.

Preface
1 Introduction
2 Basics of Stellar Magnetic Field Studies
3 Observing Magnetic Fields
4 Ap/Bp Stars
5 O- and Early B-type Stars
6 Herbig Ae/Be Stars
7 Other Objects
8 Final Remarks