The undercut is one of the most versatile modern hairstyles you can have. Growing the hair on top of the head will allow you to build volume and create a pompadour type look, or keeping it shorter will allow for the cleaner corporate look with an edge. You can keep it messy for a more casual look, or load up your hair with some oil based pomade to get the clean and slick look. The haircut will have shaved sides with long hair on the top, where hair will sort of droop over to the side creating a dramatic difference between the tops and sides.
The undercut which reached the height of fashion across northern Europe and the 1930s was the choice of young British Sportsman at the turn of the 20th century. It was particularly popular with those involved in contact Sports such as rugby. As an alternative to King Edward the VII the cut was appreciated for its clean lines and practical low-maintenance quality. It was commonly known as the island cut because of a long lock of hair sitting on top of the shaved head look like a small patch of land surrounded by water the hairstyle also took root with street gangs such as Birmingham's peaky blinders and across the Atlantic with Scottish and Irish working-class emigrants on their way to the United States.
The perception of the haircut in Europe changed when the popularity of the haircut surged within the German soldier ranks and they invaded in the early 40's. The cut was then perceived as menacing and evil. US troops called it the "whitewall" referring to the very white shaved scalp topped by darker hair, resembling the two-tone tyres popular on cars at the time. In the early 80's bands on the alternative and elector-synth scene started to wear the undercut. David Bowie was an early adopter, sporting the look in the 1977 film The Man who fell to Earth.