The FT today has a useful round-up of the recent literature on Sinn Fein. I can recommend the Murray and Tonge book, which I reviewed for the Irish World:
Nationalist revolutionaries often find themselves in strange company. Nation-alist movements are usually coalitions of radically divergent social classes and political opinions glued together for as long as “the struggle” continues. When that struggle faces its end point, be that defeat, victory or (more usually) compromise, the glue cracks and things fall apart.
What is remarkable about the Provisional Republican movement is that it has remained relatively united over the past two decades, while its leadership has dragged it from terrorist pariahs to power-sharing with unionists, with the blessing of Tony Blair. Since the IRA given its P45 by its own leadership on July 27, what will Irish republicans do with the exclusively democratic means that they tell us they now embrace? (Financial Times)