"Gamma-ray Astronomy pinpoints celestial high energy particle accelerators and may reveal the origin of the cosmic-rays, a century after their discovery. Now is a time of extraordinary opportunity. Cherenkov telescopes have opened up a new domain and more than 70 very-high energy gamma-ray sources have been detected above 100 GeV, especially by the European experiments H.E.S.S. and MAGIC. NASA's Fermi Large Area Telescope, devoted to the study of the gamma-ray sky between 20 MeV and 300 GeV, was launched in June 2008 and has published the positions of 1500 previously unknown gamma-ray sources spread across the sky.However, among all the sources detected by satellite and Cherenkov telescopes, hundreds of Galactic gamma-ray sources have no obvious counterpart at optical, radio, or X-ray wavelengths. What are these sources ? What role do they play in the Galaxy's energy budget ? Many of them must be pulsars or nebulae powered by pulsars.In this project, I propose to use my expertise in both TeV and GeV gamma-ray analysis together with the excellent links of our team with radio observatories to identify the nature of these sources, focusing on pulsars and pulsar wind nebulae as primary candidates. I further propose to use the theoretical models of these cosmic accelerators that I have developed in the past both to enhance the search, and to interpret the results. The range of competences required for the proposed research project is very large and difficult to gather in one single team: pulsar timing, experience with data analysis of extended sources and theoretical know-how in pulsar wind nebulae and high energy phenomena. The P-WIND team would therefore be unique in gamma-ray Astronomy."