This is the fourth in a series of meetings which aim at encouraging interactions and collaborations among researchers working on Cosmology and related areas (Particle Physics and Astronomy) in Portugal and Spain. Portuguese and Spanish researchers working abroad will also be most welcome. The Fourth Iberian Meeting will take place in Madrid, Spain, at the Consejo Superior de Investigaciones Científicas, on the 16th and 17th of April, 2009.

The meeting has an informal character and there is no registration fee. All participants wishing to speak can suggest a topic when they register. In case that there would be excessive demand, preference will be given to younger participants. All the time slots are of equal length (15+5 minutes), and there are no parallel sessions or posters. Participants are encouraged to present works in progress (or even being started or planned) through blackboard talks, although it is not compulsory. In this way the opportunities for constructive feedback and suggestions are enhanced, and in the long term this will lead to the development of productive synergies and collaborations.