Membranes are well-organized aggregates and represent a major component of biological cells. They consist of phospholipid bilayers that normally are impermeable for polar molecules. Likewise, specific proteins can be incorporated into the bilayers which give rise to special membrane functionalities. In the present work we examine various model membranes of unusual structure employing solid state NMR and FT IR techniques. ³¹P NMR spectroscopy is used to examine the behavior of the phospholipid headgroup region. In addition, they provide quantitative information about the lateral mobility of the lipid molecules in such membranes. The analysis of the ²H NMR studies on selectively deuterated compounds yield the reorientational and conformational behavior of the fatty acid chains in the lipid molecules. The conformational behavior also is examined by FT IR spectroscopy. Here, several characteristic vibration bands can be used to monitor the conformational disorder as function of temperature and sample composition. The studies concerning the lipid properties are accomplished by ¹³C MAS NMR spectroscopy that provide data about the fatty acid chain region, the glycerol backbone and the head group region. ²H NMR studies - perfomed on samples with D₂O- yield information about the mobility of the water component in such bilayers. Besides the investigations of the pure lipid bilayer systems particular emphasis is given to the changes of the molecular features upon the addition of other membrane components, like cholesterol or proteins. It is found that these components give rise to distinct changes in the molecular features of the lipid molecules which can be followed by the experimental techniques mentioned above.