The Sun and stars rotate in di?erent ways and at di?erent velocity rates. The knowledge of how they rotate is important in understanding the formation and evolution of stars and their structure. The closest star to our Earth, the Sun, is a good laboratory to study in detail the rotation of a G star and allows to test new ideas and develop new techniques to study stellar rotation. More or less massive, more or lessevolved objects, however, can have averydi?erent rotation rate, structure and history. In recent years our understanding of the rotation of the Sun has greatly improved. The Sun has a well-known large-scale rotation, which can be m- sured thanks to visible features across the solar disk, such as sunspots, or via spectroscopy. In addition, several studies cast light on di?erential rotation in the convective zone and on meridional circulation in the radiative zone of the Sun. Even the rotation of the core of the Sun can now be studied thanks to various methods, such as dynamics of the gravitational moments and of course, helioseismology, through g-modes analysis. Moreover, the magnetic ?eld is strongly linked to the matter motions in the solar plasma. The solar magnetic ?eld can be measured only at the surface or in theupperlayers.Itistheproductoftheinternaldynamoorofthelocaldynamos if they exist – in any case magnetic ?eld and rotation cannot thus be separated.

Starting in 1995 numerical modeling of the Earth’s dynamo has ourished with remarkable success. Direct numerical simulation of convection-driven MHD- ow in a rotating spherical shell show magnetic elds that resemble the geomagnetic eld in many respects: they are dominated by the axial dipole of approximately the right strength, they show spatial power spectra similar to that of Earth, and the magnetic eld morphology and the temporal var- tion of the eld resembles that of the geomagnetic eld (Christensen and Wicht 2007). Some models show stochastic dipole reversals whose details agree with what has been inferred from paleomagnetic data (Glatzmaier and Roberts 1995; Kutzner and Christensen 2002; Wicht 2005). While these models represent direct numerical simulations of the fundamental MHD equations without parameterized induction effects, they do not match actual pla- tary conditions in a number of respects. Speci cally, they rotate too slowly, are much less turbulent, and use a viscosity and thermal diffusivity that is far too large in comparison to magnetic diffusivity. Because of these discrepancies, the success of geodynamo models may seem surprising. In order to better understand the extent to which the models are applicable to planetary dynamos, scaling laws that relate basic properties of the dynamo to the fundamental control parameters play an important role. In recent years rst attempts have been made to derive such scaling laws from a set of numerical simulations that span the accessible parameter space (Christensen and Tilgner 2004; Christensen and Aubert 2006).

These Proceedings present the most recent results from the highly successful international solar space missions (SOHO, CORONAS-F, TRACE, RHESSI, YOHKOH) and ground observatories around the Earth, reported at the IAU Symposium 223 held in St. Petersburg, Russia, June 14-19, 2004. These include discussions of the current theories of solar dynamics and activity, new constraints provided by the multi-wavelength observations of the Sun from the interior to the heliosphere, as well as discussions of future coordinated plans and efforts of multi-wavelength investigations of the Sun. The Proceedings contain the material of seven plenary sessions and three round-table discussions

The concept of summerschools and workshops at the Kanzelh· ohe · Solar Observatory, Karn · · ten, Austria, devotedtoup-to-datetopicsinsolarphysics has been proven to be extremely successful, and thus in August/September 2003 the third combined summerschool and workshop was held there. This book contains the proceedings of the Summerschool and Wo- shop "Solar Magnetic Phenomena" held from 25 August to 5 September 2003 at the Solar Observatory Kanzelh· ohe, · which belongs to the Institute for Geophysics, Astrophysics and Meteorology of the University of Graz, Austria. The book contains the contributions from six invited lecturers. They give an overview on the following topics: observations of the pho- sphere and chromosphere, solar?are observations and theory, coronal mass ejections and the relevance of magnetic helicity, high-energy radiation from the Sun, the physics of solar prominences and highlights from the SOHO mission. The lectures contain about 25 to 30 pages each and provide a valuableintroduction to the topics mentioned above. The comprehensive lists ofreferences at theendof each contribution enablethe interested reader to go into more detail. The second part of the book contains contributed papers. These - pers were presented anddiscussed in theworkshop sessions during the afternoons. The sessions stimulated intensive discussions between the p- ticipants and lecturers