Pulsars are highly magnetized rotating neutron stars (NS) that emit beamed electromagnetic radiation and are very interesting astrophysical objects because of, among other reasons, their extreme physical conditions. However, and despite more than 40 years of observations and theory, there is no convincing pulsar emission model that explains in detail the characteristics of the radiation emitted by pulsars. Part of the problem lies in that, while more than 2000 radio pulsars are known to date, only a small fraction of them have detected emission at higher energies, making the construction of a complete picture very difficult. In this proposal we attempt at alleviating this problem by doing a systematic study of optical emission from pulsars, new pulsars detected in gamma-rays by the Fermi satellite and also on already known optical pulsars. For the new gamma-ray pulsars we will search for optical counterparts and then try to characterize their optical radiation properties, including polarisation. A similar approach will be used for the already known optical pulsars, also as part of an ongoing program. The ultimate goal will be to provide multi wavelength studies of pulsar emission, including polarisation, and to use them to constrain theoretical models of emission. A second goal is to study pulsars companions to high-mass OB-type stars (BeXs). Here, X/gamma-rays are produced by accretion of matter from the circumstellar disc around the Be star onto the NS, and by the emission of the NS itself. We plan to investigate the interaction between the viscous decretion disc around the Be star and the NS, i.e. the truncation of this circumstellar disc by the neutron star. The project will contribute to strengthen EU science by promoting collaborations among institutes and countries within the Community, and the scientific goals are well matched to those from other projects founded by the EU, e.g. OPTICON (of which the proponent is member).