The New York Review of Books has a very informative feature on him - The Last Palestinian, by Hussein Agha and Robert Malley:
Abu Mazen is a politician of conviction, which is to say, until recently, not much of a politician at all. His behavior is rarely scheming; it is, if anything, a pure outgrowth of his emotional and temperamental makeup, a feature that accounts for his many successes and not a few of his setbacks. Guided by a deep sense of ethics, repugnance for sheer political expediency, and an exaggerated faith in the power of reason, he will seldom give in or fight back when rebuffed or slighted. Convinced that he has logic and reason on his side, and equally convinced that logic and reason are the faculties that guide all others, he would much rather passively wait until in due course people see things his way. There is little of the manipulator, deceiver, or conspirator in him, which is perhaps why he is so unforgiving of the manipulations, deceptions, and conspiracies of others. [...]
Abu Mazen is also a profoundly pious Muslim. Inspired by Islam but allergic to its role in politics, he prays daily and fasts at Ramadan but publicizes neither, feeling as he does that religion is a matter of private belief, not public display, let alone public regulation. In his now regular dealings with leaders of Hamas or Islamic Jihad, this gives him an unmistakable edge; he is convinced he is no less a Muslim than they are, and when he meets a self-proclaimed Islamist politician, he sees the politician, not the Islamist.
Uncomfortable with how negotiations had proceeded up until the Camp David summit, Abu Mazen was adamantly opposed to the outbreak of violence that followed it. Violence long struck him as pointless and unsound, tantamount to using the weakest Palestinian weapon to assail Israel's strongest flank. Abu Mazen looked at violence in purely cost-benefit terms, and while the costs were high, benefits were few: Israelis closed ranks, the United States took sides, the international community turned its back, and the Palestinian Authority fell apart. Instead, he believes the goal ought to be to engage with various Israeli political groups, talk in a language that Washington understands, and rally the world to the Palestinians' cause. To that end Palestinians must stabilize the situation, restore law and order, rein in all armed militias, build transparent, legitimate centralized institutions, and, above all, cease armed attacks against Israel. In his vision, means and ends mesh: if Palestinians make a fair case, they can get a fair hearing. Out of Palestinian restraint will come both stronger international support and greater receptivity by the Israeli public to logical demands.
Hamas and Islamic Jihad are well aware that Abu Mazen's program is incompatible with theirs, that he rejects violence and the existence of armed militias. But they have lived with him before, and are confident they can do so again. They believe they know his ways—to co-opt, not to crush. Convinced that Israel will not give him a fair chance and that he therefore will fail, they can afford to wait for the next round while benefiting from an overdue respite. As for the the US, Israel, Europe, and Arab countries, Abu Mazen not only believes in the agenda they claim to hold dear—ending armed attacks, building Palestinian institutions, asserting the rule of law—but, more significantly, is viewed as the only Palestinian remotely capable of delivering it.
Among this wide array of domestic and international constituents, those who adhere fully to his political vision are few and those who believe he ultimately will see things their way are many. But for now, Abu Mazen is relatively free to speak and act on his own, freer no doubt than either he or most others expected. Because they came to him rather than he to them, he is under surprisingly little pressure from the very same groups that Arafat perpetually sought to placate and that, in turn, sought to tie his hands. Whatever competing centers of power once existed are for now essentially dormant, unwilling or unable to form an organized and effective opposition. Perhaps most importantly, he has achieved this position because more than any other Palestinian leader today his political inclinations are in harmony with his people's immediate priorities: security and the aspiration for a normal life free of fear of Israeli attacks and Palestinian gangs; material betterment and resumption of basic economic activity; and freedom of movement, the ability once again to circulate without constant roadblocks, curfews, and humiliation. Ironically, Palestinians now aspire to many of the conditions that prevailed prior to the intifada, conditions that to a large extent set it off, and that, in their minds, Abu Mazen is best equipped to restore. [...]
Hopefully, things will begin to improve soon.