Specialist (rank)
On 1 July 1955 four grades of Specialist were established. The first was Specialist Three (E-4). It is the only one that still exists. It was changed to Specialist Four in 1958. Specialist Two (E-5), Specialist One (E-6), and Master Specialist (E-7) were also created in 1955. These were all eventually replaced with other titles. In 1958 the DoD added two more pay grades. This gave enlisted soldiers more opportunities to progress to a full career. These were Specialist Eight (E-8) and Specialist Nine (E-9) which were abolished in 1968. All except SP4 were abolished in 1984 when SP4 was renamed as "Specialist" and abbreviated as "SPC".