Close but detached binaries consisting of a white dwarf and a main sequence star are important objects for the understanding of the evolution of compact binaries such as cataclysmic variables (CVs), supersoft X-ray sources, and X-ray binaries. Since they are still detached, no accretion takes place, and both stars can be studied without the strong light contamination from an accretion disc. In CVs themselves, it has so far only been possible for a few special systems to get spectral information for the secondary star (i.e. the donor star). These systems, in fact, show peculiar abundances. If it can be confirmed from the study of pre-CVs, that the secondary stars are much more evolved than theoretically predicted, this could be a way to explain the still present mismatch between the observed and predicted period distribution of CVs. We have a large ongoing project to examine these binaries with the special aims of finding those systems which will eventually evolve into cataclysmic variables and to study their secondary stars via optical and IR spectroscopy. Here we show some recent results of this project and present the binary parameters and the analysis of the secondary stars for several Pre-CV systems.