He specializes in the history of the holocaust Period and World War II, Modern Jewish history, history of the Concentration and Extermination Camps, particularly Auschwitz, Majdanek and Jasenovac. Greif received his bA and MA in Jewish history, The History of Eretz Israel, and his Ph.D. in Jewish modern history. his mentor and professor was the coryphaeus of the history of the holocaust on the territory of Yugoslavia, a professor from Israel, Menachem Shelah. During the course of his studies, as well as upon finishing them, he has authored a number of radio documentaries and documentary films on the subject of World War II, the Holocaust, and the like. Professor Greif worked as a professor, lecturer, and researcher at universities in Tel Aviv, Vienna, Austin, Miami, and other places. for many years he has been the Director of the Germany and Poland Desk within the European Department of the Yad Vashem in Israel, has edited various publications, worked as a historian, pedagogue, lecturer, and senior researcher at this world-renowned institution. Throughout the many years of his work in these fields, he has authored and edited numerous texts and papers as well as books, such as, for example, We Wept without Tears, a book that inspired the award-winning film Son of Saul. His papers and books are published in many languages. He was engaged as an author and participated in the preparation of several encyclopedias of the holocaust which were published in several languages. At the moment he is the chief historian and researcher at the Shem Olam Holocaust Institute for Education, Documentation, and Research in Israel, senior historian, and researcher at the foundation for Holocaust Education Projects in Miami, Florida, lecturer at the Tel Aviv University as well as in other academic centers in Israel, advisor, translator, and interpreter at the Auschwitz-Birkenau State Museum in Poland, a Member of the American International Advisory Council of Interviewers at the Auschwitz Jewish Center Foundation of New York, located in Auschwitz, Poland.