Mahmoud Abbas, also known as Abu Mazen, was born in Safad in 1935. When he was 13, he left for Syria to become a teacher, and eventually earned a law degree from Damascus University. From there he travelled to Moscow, earning his doctorate in History at Oriental University. There he met many anti-Zionist factions who believed that the Jews were bent on world domination. He wrote his doctoral thesis on connections between certain Zionist groups and the Nazis. He is somewhat of a Holocaust revisionist, believing that the Jews overstated their losses for their own personal gain, although he has tempered his beliefs (or rather, made them less public) since his university days.
Upon graduating, he began working in Qatar's government as a personnel director and began forming groups whose goals were centered around the autonomy of Palestine. He helped found Fatah, and joined the PLO Executive Committee in 1970. Throughout the 70s he was one of the few PLO members who initiated and attended dialogues with Israel over such issues as curfews, illegal searches, and the economy. It was his talks with Matiyahu Peled that led to the "principles of peace", part of the contingent of the two-state solution issued in 1977.
In 1980, he was named the chair of the PLO Department for National and International Relations and, upon the assassination of Abu Jihad in 1988, took over as chairman of the portfolio on the Occupied Territories. In 1993, he headed the negotiating team at the now somewhat infamous Oslo accords, and it is signature at the bottom of the accord on behalf of PLO.
In 1995, Abbas returned home after 48 years in exile, settling in Ramallah, where he wrote a bestselling book narrating the events of the Oslo meeting entitled Through Secret Channels: The Road to Oslo. That same year he drafted the Abu-Mazen-Beilin plan with Israeli deputy prime minister Yossi Beilin, although the contents of the plan would not be published until 2000.
Finally, in 1996, Abbas was elected to be the secretary general of the Executive Committee, sealing his position as Yasser Arafat's second in command. In addition to this role, he served as a representative for Qalqilya in the Palestine Legislative Council, and in March of 2003 he was elected the first prime minister of the Palestinian Authority, moving along the road map to peace and giving the Middle East hope of a smooth and well-developed resolution.
Despite Abbas' position, he was not given full authority by Arafat to do as he will; most importantly, Abbas was denied several security clearances that would have helped him deal with Palestinian groups committing terrorist acts in Israel. Helpless, Abbas refused to dismantle the terrorist groups in Palestine, instead resigning just four months later. Considered too conciliatory by the Palestinians and too reluctant by the Israelis, Abbas was content to return to a more subservient and behind-the-scenes position in Palestine.
Fun Fact: Mahmoud Abbas' second name Abu Mazen comes from Muslim tradition. "Abu" means "father", and Muslims take on a second name when they have their first born son. Hence, Abbas' first child is apparently named Mazen, and thus Abu Mazen. Yasser Arafat is called Abu Amar, though he has no children.