I wonder how many people have ever heard the name "Sabina Spielrein." Certainly not as many as have heard the names of Carl Jung, Sigmund Freud, Jean Piaget, and Lev Vygotsky. While Spielrein had numerous face-to-face encounters, some personal and some professional, with all four men, and the accounting of her life and the interactions she had with them has been the content of numerous publications (Kerr, 1993; Marton, 2002), the story of what she contributed to their lives and works has not been told. To that end, this article will concisely describe how Sabina Spielrein's life, work, and theories influenced the theories of Jung, Freud, Piaget, and Vygotsky. The professional contributions of numerous women in the 19th and 20th centuries were marginalized or even credited to men. In essence, many of these women were callously cheated out of the credit they were due. For example, according to Sadker and Sadker (1994), Catherine Littlefield (Kitty) Greene had as much to do with the invention of the cotton gin as Eli Whitney. She "came up with the breakthrough idea of using brushes for the seeds" (p. 67). However, Eli Whitney was credited with inventing the machine and was given full title to it. At that time, "It was especially unlikely for a lady to patent an invention. Textbooks tell the story of names registered in the patent office, but they leave out how sexism and racism denied groups of people access to that registry" (p. 67).