Over the last few decades, there have appeared several research groups in Spain with a strong interest in Lorentzian geometry. This was not corresponded with a suitable interrelation among their protagonists. Thus, it seemed worthwhile to organise a series of periodical meetings allowing a better understanding of the research activity and promoting scientific exchange and collaboration in this area of mathematics. In addition, a key element in these scientific meetings is to encourage the participation of young students and new researchers in the field. In order to serve this purpose, the congress "Lorentzian Geometry. Benalmádena 2001" was organised. Its aim was to gather researches interested in Lorentzian geometry in a suitable framework. The excellent results achieved during this meeting were reported in subsequent meetings (Geometría de Lorentz, Murcia 2003 and III International Meeting on Lorentzian Geometry, Castelldefels 2005) as "the spirit of Benalmádena".

The present congress intends, on the one hand, to keep alive this atmosphere of communication and, on the other hand, to introduce two important improvements: the internationalisation, by promoting new contacts and enhance co-operation with other foreign groups interested in Lorentzian geometry, and the collaboration with physicists, as it is essential to foster interaction and exchange of knowledge among researchers of different areas which have, nevertheless, a common and well defined stem. We consider that this interaction is positive and fruitful, both for researchers involved in fundamental science and for those interested in possible applications. What is more, we are convinced that no researcher should lose contact with basic science or its applications.

In relation with this last objective, we would like to emphasise that a School on Lorentzian Geometry is going to take place simultaneously with this congress. This school is organised as a complementary activity and is specially aimed at PhD students and young researchers. This activity is one of the events organised under the framework of the Thematic Network of Relativity and Gravitation and the timetables will be compatible. Both events will suppose a mutual benefit to each other and will allow students and young researchers attending the school to make contacts and widen their horizons in Lorentzian geometry.

Finally, we would like to remind that an only registration is required, covering all the activities for both the IV International Meeting and the School on Lorentzian Geometry, which will take place in the Faculty of Mathematics of the University of Santiago de Compostela.