A review of recent developments in microwave spectroscopy techniques in the Terahertz range and some examples of molecular spectra achieved at the Nizhnii Novogorod Microwave Spectroscopy Laboratory are presented. Techniques and methodics developed include: development (jointly with the KVARZ Institute of Electronic Measurements, Nizhnii, Novogorod) of a unique series of commercial frequency synthesizers covering the 53–178 GHz range, which are now used in several Western Laboratories; development of laboratory versions of synthesizers up to frequencies exceeding 500 GHz; development (jointly with the Physical Institute of the University of Cologne, Germany) of precise microwave broadband scanning spectrometers covering a range exceeding 1 THz; development of alternative (non-synthesizer based) techniques of microwave spectroscopy in the submillimeter range; extension of the range of microwave spectroscopy up to 1.5 THz by multipication of frequency of the submillimeter backward wave oscillators. New objects of submillimeter microwave spectroscopic studies include: spectra of molecular complexes in equilibrium and in supersonic jets; spectra of some light molecules; studies of effects connected with high excitation of vib-rot states: clustering of energy livels in asymmetric tops: development of new methods for describing the spectra of non-rigid molecules and their applications. Further studies of molecular interactions (pressure line shifts and broadenings) include: achievement of new measurement accuracy limits; study of the shape of strongly shifted lines; studies of the temperature dependence of shift and broadening and its applications; study of some new effects: experimental demonstration of the existence of non-additivity of pressure lineshifts in the system of molecular transitions; experimental demonstration of the absence of non-additivity of pressure lineshifts in mixtures of gases. The studies of molecular spectra and molecular interactions were carried out, in part, jointly with the University of Cologne, University of Giessen, Kiel University, Wuppertal University, Molecular Physics Division of the National Institute of Standards and Technology, and London University. Some perspectives for the development of submillimeter microwave spectroscopy techniques discussed in this paper include: further extension of the range of microwave spectroscopy well beyond 1.5 THz; extension of the range of frequency synthesizers; some non-spectroscopical applications of the techniques and methods developed.