"[...]The book provides an interesting selection of topics of current interest and brings together several different areas of gravitation and cosmology, most notably mathematical and experimental issues, which are not commonly found in one book. Overall, the book is interesting for its combination of theoretical and mathematical aspects of gravity and cosmology with issues closely related to experiment and observation. It should be of interest both to young cosmologists or relativists starting their career and to specialists aiming at broadening their general knowledge in several topics of current interest in cosmology and gravitation." (Marc Mars, University of Salamanca in General Relativity and Gravitation, 36:1, January 2004)