The purpose of this talk is to demonstrate how a tool chest of soft x-ray and electron spectroscopies (in particular using high-brilliance synchrotron radiation) is uniquely suited to unravel the electronic and chemical properties of surfaces and interfaces in thin film solar cells. We will show how photoelectron spectroscopy (PES), Auger electron spectroscopy (AES), inverse photoemission (IPES), x-ray emission spectroscopy (XES), and x-ray absorption spectroscopy (XAS) can be suitably combined to derive band gaps, study local chemical bonding and electronic level alignment, and derive insights into chemical stability at surfaces and interfaces. As examples, Cu(In,Ga)(S,Se)2 and CdTe thin films and devices will be discussed.