Infrared plus vacuum ultraviolet (IR/VUV) photoionization spectroscopy can be employed to elucidate the structures, properties, and unimolecular reactivities of hydrogen bonded systems. The use of VUV radiation eliminates the need for the presence of UV chromophores in the molecules, and therefore the IR/VUV technique potentially has broader applicability than the conventional IR/UV double resonance technique.  This advantage results from the fact that a single VUV photon has sufficient energy to ionize molecules and clusters without the need for an intermediate state, as required for UV resonance enhanced multiphoton ionization (REMPI). This review reports and summarizes a variety of chemical, physical, structural, and electronic properties determined by IR/VUV and IR/UV spectroscopic techniques.  The systems discussed in this context include aliphatic and aromatic alcohols, acids, and amines.  Both unimolecular and clustered species can be accessed by the experimental and theoretical approaches presented. Buy this Article