Recent experiments on Scanning-Tunneling Microscopy imaging of individual molecular orbitals and orbitals of metal atom - molecule complexes are reviewed and analyzed theoretically. In these experiments ultrathin insulating films have been employed to decouple individual molecules electronically from the metallic substrate. As a result a double tunnel barrier is formed, and inelastic electronic tunneling spectroscopy can be performed to investigate electronic states in molecules, charging and vibrational effects.