The recent scientific efforts in Astrophysics & Cosmology have brought a revolution to our understanding of the Cosmos. Amazing results is the outcome of amazing experiments! The huge scientific, technological & financial effort that has gone into building the 10-m class telescopes as well as many space and balloon observatories, essential to observe the multitude of cosmic phenomena in their manifestations at different wavelengths, from gamma-rays to the millimetre and the radio, has given and is still giving its fruits of knowledge.
These recent scientific achievements in Observational and Theoretical Cosmology were presented in the "Multiwavelength Cosmology" conference that took place on beautiful Mykonos island in the Aegean between 17 and 20 June 2003. More than 180 Cosmologists from all over the world gathered for a four-day intense meeting in which recent results from large ground based surveys (AAT/2-df, SLOAN) and space missions (WMAP, Chandra, XMM, ISO, HST) were presented and debated, providing a huge impetus to our knowledge of the Cosmos.
The future of the subject (experiments, and directions of research) was also discussed. The conference was devoted mostly on the constraints on Cosmological models and galaxy formation theories that arise from the study of the high redshift Universe, from clusters of galaxies, and their evolution, from the cosmic microwave background, the large-scale structure and star-formation history.

The reviews presented in this volume cover a huge range of cluster of galaxies topics. Readers will find the book essential reading on subjects such as the physics of the ICM gas, the internal cluster dynamics, and the detection of clusters using different observational techniques. The expert chapter authors also cover the huge advances being made in analytical or numerical modeling of clusters, weak and strong lensing effects, and the large scale structure as traced by clusters.

Manolis Plionis & Spiros Cotsakis plionis@sapfo. astro. noa. gr skot@aegean. gr Since the dawn of human civilisation natural phenomena have been subject to observation and investigation by the humans who initially ascribed to them 'divine' powers. Gods of 'good' and 'evil' werecreatedaccording to the useful- ness or notofsuch unexplained, atthetime, phenomena. Astheir understanding of the world developed and deepened, the divine powers, religious beliefs, su- perstitions and mysticism gave their place to the knowledge, limited that it may be, of physical reality. However, many issues have been and still are out of grasp of human understanding. These issues have always been at the center of philosophical, theological, and more recently, scientific debate. It is to us incredible that many of the conclusions concerning the true scientific explanation of the external world, to which the ancient Greeks arrived purely on the basis of abstract thought, came so near to modem scientific ideas and also form the basis of modem science. We cannot but stand with amazement at the original thoughts of Archimedes who, among his many extraordinary achieve- ments in mathematics and physics, calculated (cf. TheSandReckoner) the mass density of the observable universe and came up with a figure that is in complete agreement with current estimates coming from observational cosmology.

The reviews presented in this volume cover a huge range of cluster of galaxies topics. Readers will find the book essential reading on subjects such as the physics of the ICM gas, the internal cluster dynamics, and the detection of clusters using different observational techniques. The expert chapter authors also cover the huge advances being made in analytical or numerical modeling of clusters, weak and strong lensing effects, and the large scale structure as traced by clusters.

Manolis Plionis & Spiros Cotsakis plionis@sapfo. astro. noa. gr skot@aegean. gr Since the dawn of human civilisation natural phenomena have been subject to observation and investigation by the humans who initially ascribed to them 'divine' powers. Gods of 'good' and 'evil' werecreatedaccording to the useful- ness or notofsuch unexplained, atthetime, phenomena. Astheir understanding of the world developed and deepened, the divine powers, religious beliefs, su- perstitions and mysticism gave their place to the knowledge, limited that it may be, of physical reality. However, many issues have been and still are out of grasp of human understanding. These issues have always been at the center of philosophical, theological, and more recently, scientific debate. It is to us incredible that many of the conclusions concerning the true scientific explanation of the external world, to which the ancient Greeks arrived purely on the basis of abstract thought, came so near to modem scientific ideas and also form the basis of modem science. We cannot but stand with amazement at the original thoughts of Archimedes who, among his many extraordinary achieve- ments in mathematics and physics, calculated (cf. TheSandReckoner) the mass density of the observable universe and came up with a figure that is in complete agreement with current estimates coming from observational cosmology.