Carl Gustav Jung was an Austrian psychologist and former protegee of Sigmund Freud. He wrote a book entitled “Psychological types” (Jung, 1921) where he laid the groundwork for among others the Myers-Briggs type indicator , the KTS-II and Socionics. All of these systems build on the basic types outlined by Jung.
The Myers-Briggs type indicator was invented by Katharine Briggs and Isabel Briggs-Myers used the types outlined by Jung to develop the MBTI which was first published in 1962.
Concurrently to the development of the MBTI, a lithuanian economist and sociologist by the name of Aušra Augustinavičiūtė had gotten a hold of Carl Jung’s book through the Iron Curtain and developed socionics in the 1970s and 1980s. For those who are interested there are more information on socionics in other posts under the socionics category.
The systems have semantic differences but are largely comparable and you can find my consolidation of the 2 systems in a seperate post.
The focus of the 2 systems are different, while the focus of Isabel Briggs-Myers was focused on improving relationships, Socionics had a stronger focus on the purpose of each type in society. This lead to Socionics developing tables of intertype relations, and an 8 function model much sooner.
So, if you want to join me in putting people in little glass boxes and poking them with sticks, have a look around at my other posts on the topic.