Politicians generally fall into two categories: those who yearn for power and know what to do when they achieve it, and those who revel in being out of the "inside loop", thereby retaining their ideological purity. Oskar Lafontaine belongs to the latter group.
He is a colourful politician whose deeply held socialist convictions have caused him no end of personal dilemmas in his journey from prime minister of Saarland to his dismal failure as the SPD's candidate for the chancellorship, and his flouncing resignation after only a few months as finance minister in the Schroder cabinet. Number twos invariably think they should be number one; but whereas John Prescott has learnt the art of compromise in government, Lafontaine's personal vanity and self-importance led him inevitably into the political wilderness.
When I lived in Germany, in the 1980s, Lafontaine was considered a bit of a card - harmless, because of his position as leader of one of Germany's smallest Lander, but revered, too, for his ranting denunciations of all things Christian Democrat. Not for nothing was he known as "Red Oskar". He was the Franz-Josef Strauss of the left, a figure powerful enough to become semi-detached from his own party. And so it proved.
Lafontaine's political career was launched by his mentor, Willy Brandt, with whom he eventually had a painful parting of ways. Towards the end of his life, Brandt was consumed by supporting Helmut Kohl's drive towards reunification, and, in particular, his proposal to equate one Deutschmark to one Ostmark.
Lafontaine went out on a limb in opposing this policy but, with the notable exception of Schroder, he failed to take his party with him. Worst of all, he was proved right.
There is no disguising Lafontaine's disgust at many aspects of Tony Blair's "Third Way", which he scathingly describes as "a hodge-podge of platitudes and a rehash of principles". Indeed, the publication of the Blair-Schroder "New Centre" manifesto confirmed all Lafontaine's worst fears. Could he have become a little jealous of the burgeoning relationship between the chancellor and Tony Blair? After all, it was certainly threatening to eclipse Lafontaine's own friendship with Lionel Jospin. Understandably, as a Saarlander, Lafontaine's first priority has always been to maintain the closest of relationships with France. "No country is so dependent on the achievement of European unity as Germany," he writes. "And that unity can only be achieved in collaboration with France. Great Britain will continue to follow its own line for the foreseeable future." No wonder the Sun dubbed him the "most dangerous man in Europe".
It is remarkable how much the key personalities in left-of-centre British and German politics seem to despise each other. For Cook hating Mandelson hating Mowlam hating Brown hating everyone, substitute Scharping, Vogel, Schroder and Lafontaine. Just as policy disagreements helped bring an end to the last two right-of-centre governments in Britain and Germany, Lafontaine's book makes clear, however unintentionally, that it is the abundance of personality clashes that will do the same for the current administrations in both countries. Michael Portillo once said that the Major Cabinet was a Cabinet of chums: on a personal level, they actually rather liked each other. The Blair and Schroder cabinets are like vipers' nests. Both may meet sticky ends.
Lafontaine was the first German politician on the left to recognise that in order to get back into government, a red-green coalition would be necessary. Indeed, he was advocating this in the mid-1980s, a full decade ahead of most of his contemporaries. But in many ways the SPD, like the Labour Party, is a coalition in itself. He complains bitterly of the difficulty of governing with four conflicting centres of power - the party executive, the chancellor's office, the parliamentary party and the upper house. Lafontaine wanted complete control of all of them, but ended up with nothing. He now sits in his Saarland home, brooding, imagining what might have been, revelling in every mistake made by the Schroder government. His experience should serve as a warning for every new Labour Cabinet minister.
Iain Dale is the co-owner of Politico's Bookstore and Publishing