Mid-Century modern is an architectural, interior, product and graphic design that generally describes mid-20th century developments in modern design, architecture and urban development from roughly 1933 to 1965.
Modern architecture or Modernist architecture is a term applied to an overarching movement, with its exact definition and scope varying widely. The term is often applied to modernist movements at the turn of the 20th century, with efforts to reconcile the principles underlying architectural design with rapid technological advancement and the modernization of society.
The concept of modernism is a central theme in the efforts of 20th century modern architecture. Gaining global popularity especially after the Second World War, architectural modernism was adopted by many architects and architectural educators, and continued as a dominant architectural style for institutional and corporate buildings into the 21st century. Modernism eventually generated reactions, most notably Postmodernism which sought to preserve pre-modern elements, while "Neo-modernism" has emerged as a reaction to Post-modernism.
Notable architects important to the history and development of the modernist movement include Ludwig Mies van der Rohe, Le Corbusier, Walter Gropius, Erich Mendelsohn, Frank Lloyd Wright, Louis Sullivan, Gerrit Rietveld, Bruno Taut, Arne Jacobsen, Oscar Niemeyer and Alvar Aalto.
It was at this time, during the 1920s, that the most important figures in Modern architecture established their reputations. The big three are commonly recognized as Le Corbusier in France, and Walter Gropius and Ludwig Mies van der Rohe in Germany, all of whom trained under Peter Behrens.
Gropius and Mies van der Rohe both served as directors of the Bauhaus, one of a number of European schools and associations concerned with reconciling craft tradition and industrial technology. Mies van der Rohe designed the German pavilion (known afterward as the Barcelona Pavillon) at the 1929 Barcelona International Exposition. Villa Savoye, by Le Corbusier and his cousin, was built from 1928 to 1931. As in Russia, political pressures turned against the modernists. With the rise of Nazism in 1933, the German experiments in modernism were replaced by more traditionalist architectural forms.
World War II (1939–1945) and its aftermath was a major factor in driving innovation in building technology, and in turn, architectural possibilities. The wartime industrial demands resulting in a supply shortage (of such things as steel and other metals), in turn leading to the adoption of new materials, and advancement or novel use of old ones. Similarly, surplus postwar industrial capacity accelerated the use of new materials and techniques, particular architectural aluminium (as a result of advances made in its use in aircraft, etc., during the war). At the same time, there was a rapid demand for structures during the war (such as military and governmental facilities) as well as for housing after the war.
After World War II the Congrès Internationaux d'Architecture Moderne (CIAM) was a force in shaping modernist urban planning, and consequently the design of cities and the structures within, from 1928 to 1959. Its 1933 meeting resulted in the basis of what became the Athens Charter, which would drive urban planning practice for much of the mid-20th century. Following its principles, in the late 1950s the entirely-new city of Brasília was built as a new capital for Brazil, designed by Lucio Costa, with prominent works for it designed by Oscar Niemeyer. Le Corbusier applied CIAM's principles in his design for the city of Chandigarh in India.
The devastation that WWII wrought in Europe, Asia, and the Pacific and subsequent post-war housing shortages resulted in a vast building and rebuilding of cities, with a variety of techniques employed for the creation of mass-housing. One attempt to solve this was by using the Tower block. In the Eastern Bloc, mass housing took the form of prefabricated panel buildings, such as the Plattenbau of East Germany, Khrushchyovka of Russia and the Panelák of Czechoslovakia.
Arising shortly after the end of World War II, a particular set of stylistic tendencies in the United States during this time is known as Googie (or "populuxe"), derived from futuristic visions inspired by the imagery of the Atomic Age and Space Age, with motifs such as atomic orbital patterns and "flying saucers", respectively, such as in the Space Needle in Seattle. Though the style was unique to the United States, similar iconography can be seen in the Atomium in Brussels.
Googie architecture is a form of modern architecture, a subdivisionof futurist architecture influenced by car culture, jets, the Space Age, and the Atomic Age. Originating in Southern California during the late 1940s and continuing approximately into the mid-1960s, Googie-themed architecture was popular among motels, coffee houses and gas stations. The school later became widely known as part of the Mid-Century modern style, elements of which represent the populuxe aesthetic, as in Eero Saarinen's TWA Flight Center. The term "Googie" comes from a now defunct coffee shop and cafe built in West Hollywood designed by John Lautner. Similar architectural styles are also referred to as Doo Wop. 
Features of Googie include upswept roofs, curvaceous, geometric shapes, and bold use of glass, steel and neon. Googie was also characterized by Space Age designs symbolic of motion, such as boomerangs, flying saucers, atoms and parabolas, and free-form designs such as "soft" parallelograms and an artist's palette motif. These stylistic conventions represented American society's fascination with Space Age themes and marketing emphasis on futuristic designs. As with the Art Deco style of the 1930s, Googie became less valued as time passed, and many buildings in this style have been destroyed.
Brutalist architecture is a fragmented movement in architecture that flourished from the 1950s to the mid-1970s, descended from the modernist architectural movement of the 1930s. Brutalism became popular with government and institutional clients, with numerous examples in Britain, France, Germany, Japan, United States, Canada, Brazil and Australia. Examples are typically massive in character, fortresslike, with a predominance of exposed concrete construction, or in the case of the "brick brutalists" ruggedly detailed brickwork and concrete together. There is often an emphasis on graphically expressing in the external elevations and in the whole-site plan the main functions and people-flows of the buildings. Brutalism became popular for educational buildings (especially university buildings), but was relatively rare for corporate projects. Brutalism became favoured for many government projects, high-rise housing, and shopping centres to create an architectural image that communicated strength, functionality, and frank expression of materiality.
Seen in the work of Le Corbusier from the late 1940s with the l'Unité d’Habitation in Marseille, the term Brutalism was first used in England by the architectural historian Reyner Banham in 1954. It referred to the work of Alison and Peter Smithson’s school at Hunstanton in Norfolk because of its uncompromising approach to the display of structure and services, albeit in a steel building rather than reinforced concrete.
Brutalist buildings are usually formed with repeated modular elements forming masses representing specific funcional zones, distinctly articulated and grouped togehter into an unified whole.
Concrete is used for its raw and unpretentious honesty, contrasting dramatically with the highly refined and ornamentad buildings constructed in the elite Beaux-Art style.
Another common theme in Brutalist designs is the exposure of the building's functions in the exterior of the building. In the Boston City Hall designed in 1962, the strikingly different and projected portions of the building indicate the special nature of the rooms behind thoses walls. From another perpective, the design of the Hunstanton School included placing the facilitie's water tank, normally a hidden service feature in a prominent, visible tower.
Brutalism as an architectural philosophy was often also associated with a socialist utopian ideology, which tended to be supported by its designers, especially Alison and Peter Smithson, near the height of the style. This style had a strong position in the architecture of European communist countries from the mid-1960s to the late 1980s. In Czechoslovakia, brutalism was presented as an attempt to create a "national" but also "modern socialist" architectural style.
More info: http://www.brutalismus.com