LHCII, the largest plant photosynthetic pigment-protein complex of photosystem 
II, is a most abundant membrane protein in living organisms and comprises 
approximately half of the pool of chlorophyll molecules in the biosphere. The 
principal role of this pigment-protein complex is to collect sunlight quanta and 
transfer electronic excitations toward the reaction centers, where the primary 
photosynthetic electric charge separation reactions take place. The LHCII 
protein, as a major protein component of the photosynthetic membranes, modulates 
also the structural and dynamic properties of the lipid phase of the membranes. 
According to the recent concepts, one of the physiological roles of LHCII is 
also a protection of the photosynthetic apparatus against oxidative damage 
caused by illumination with high intensity light. Detailed examination of all 
those physiological functions of LHCII, in relation to the complex structure, 
was possible owing to the application of several molecular spectroscopy 
techniques. Some examples of such studies are presented in this chapter. The 
examples of application of steady-state and time-resolved fluorescence 
spectroscopy, Fourier-transform infrared absorption spectroscopy, and resonance 
Raman scattering spectroscopy are presented and discussed.