I've known Ahtisaari since 2000, when he took on the chairmanship of my then future employers, the International Crisis Group, and so we saw each other a fair bit at Balkan events in Brussels. We also chatted then about his role in the Northern Ireland peace process. I joined ICG as director of their Balkans programme in 2002, and at our first internal meeting I quoted Shaw's line from John Bull's Other Island about one's duty to Ireland, Finland and Macedonia; Ahtisaari laughed much louder than one expects from a Finn. He left the ICG board in 2004, but we stayed in contact as he was put in charge of the UN process of finding a final status for Kosovo; I remember one visit to his office in Vienna where our conversation was delayed by his trying to get his latest Nokia gadget to work (his son at the time was Nokia's director of design strategy). Ahtisaari is fascinated by the role technology can play in helping to resolve conflict, and as well as other continuing behind-the-scenes work, he is these days most involved with his Crisis Management Initiative, which will carry on his vision into the future (he is 71).
The Nobel Peace Prize often goes to interesting people, and I've met several others who have won it, but this is the first time it has gone to someone I know at all well; and he richly deserves it.