This is a stamp of a institution that is long gone. The “Pädagogisches Zentrum” (pedagogical centre) in Berlin was an institution for study and research for teachers. It lasted form 1964 up until 1994. Also on this picture: An even older stamp from a “Studienbücherei für Lehrer” (study library for teachers) in the urban district of Zehlendorf.
You see the ink makes the stamp look a liitle bit blurry.
The safety stamp in the middle of the book – obviously smaller and oval.
And a stamp next to a book card flap.