Transfer Path Analysis (TPA) designates the family of test-based methodologies to study the transmission of mechanical vibrations. Since the first adaptation of electric network analogies in the field of mechanical engineering a century ago, a multitude of TPA methods have emerged and found their way into industrial development processes. Nowadays the TPA paradigm is largely commercialised into out-of-the-box testing products, making it difficult to articulate the differences and underlying concepts that are paramount to understanding the vibration transmission problem. The aim of this paper is to derive and review a wide repertoire of TPA techniques from their conceptual basics, liberating them from their typical field of application. A selection of historical references is provided to align methodological developments with particular milestones in science. Eleven variants of TPA are derived from a unified framework and classified into three categories, namely classical, component-based and transmissibility-based TPA. Current challenges and practical aspects are discussed and reference is made to related fields of research. degree of freedom frequency response function dynamic displacements/rotations applied forces/moments interface forces/moments admittance FRF matrix impedance FRF matrix transmissibility matrix pertaining to the assembled system pertaining to the active/passive component pertaining to the test rig source excitation DoF interface DoF receiver DoF indicator DoF pseudo-force DoF 
General framework for transfer path analysis: History, theory and classification of techniques