problems could now be solved by dividing the problem into subdomains, each processed by a separate processor, and solving for the interface coupling iteratively. This can be seen as a second level domain decomposition as is visualized in the figure. The efficiency of dynamic modelling could be increased even further by reducing the complexity of the individual subdomains. This reduction of the subdomains (or substructures in the context of structural dynamics) is realized by representing substructures by means of their general responses. Expressing the separate substructures by means of their general response instead of their detailed discretization led to the so-called dynamic substructuring method. This reduction step also allowed for replacing the mathematical description of the domains by experimentally obtained information. This reduction step is also visualized by the reduction arrow in the figure. The first dynamic substructuring methods were developed in the 1960s and were more commonly known under the name component mode synthesis (CMS). The benefits of dynamic substructuring were quickly discovered by the scientific and engineering communities and it became an important research topic in the field of structural dynamics and vibrations. Major developments followed, resulting in e.g. the classic Craig-Bampton method. Due to improvements in sensor and signal processing technology in the 1980s, substructuring techniques also became attractive for the experimental community. Methods dealing with structural dynamic modification were created in which coupling techniques were directly applied to measured frequency response functions (FRFs). Broad popularity of the method was gained when Jetmundsen et al. formulated the classical frequency-based substructuring (FBS) method, which laid the ground work for frequency-based dynamic substructuring. In 2006 a systematic notation was introduced by De Klerk et al. in order to simplify the difficult and elaborate notation that had been used prior. The simplification was done by means of two Boolean matrices that handle all the "bookkeeping" involved in the assembly of substructures Domains Dynamic substructuring can best be seen as a domain-independent toolset for assembly of component models, rather than a modelling method of its own. Generally, dynamic substructuring can be used for all domains that are well suited to simulate multiple input/multiple output behaviour. Five domains that are well suited for substructuring are: Physical domain Modal domain Frequency domain Time domain State-space domain The physical domain concerns methods that are based on (linearised) mass, damping and stiffness matrices, typically obtained from numerical FEM modelling. Popular solutions to solve the associated