The book's subject is the Ostpolitik, West Germany's policies towards eastern Europe, East Germany and the Soviet Union between 1966 - when Willy Brandt became foreign minister - and the formal unification of Germany in 1990. Before the Ostpolitik, West Germany was locked into a denial of the 'realities' of post- Yalta Europe. East Germany was 'the Soviet occupation zone'; Poland's new frontier on the Oder-Neisse line was repudiated; Bonn had no formal relations with any east Eurpopean state except the Soviet Union. Under Brandt, who became Chancellor in 1969, and his successors Schmidt and Kohl, West Germany began to recognise the 'realities'. New frontiers were accepted; East Germany's 'existence' (not quite its 'foreign' sovereignty) was recognised; diplomatic relations were opened; a network of political and economic treaties was woven between West Germany and its eastern neighbours.
The motives were many-layered. There was the simple wish to catch up: to recognise what West Germany's western partners already recognised. There was the moral imperative which made Willy Brandt kneel before the monument to the Warsaw ghetto rising: reconciliation with those peoples who had suffered most from Hitlerism. But then came a series of paradoxical maxims, which Garton Ash explores with intelligent irony. The status quo in Europe was to be overcome by accepting it. The unification of Germany was to be hastened by ceasing to demand it. The freedom of populations living under Communism was to be increased by befriending Communist leaders - the authors of unfreedom. The destabilisation of East Germany was to be achieved by stabilising it - by lavish loans and programmes of political co-operation.
Now we live in a different world, and ask painful questions with hindsight. In Berlin, in united Germany, a parliamentary commission charged to study the East German dictatorship is asking them - and the witnesses have included not only the surviving architects of Ostpolitik but Timothy Garton Ash himself.
The first question is whether it worked. In the event, Communism in eastern Europe was not diluted away by German reassurances but suddenly overthrown by its peoples; the promises of non- intervention which mattered in 1989 were not Kohl's but Gorbachev's. The second question is whether the 'befriending' got out of control and slithered into smarmy collaboration with dictatorships against their subjects. Garton Ash has studied many of the East German files, even interviewing Erich Honecker in a Berlin prison, and some of his evidence is frightening. In private, some West German politicians assured Honecker's men that they would give no encouragement to the tiny democratic opposition and - in one odious instance - advised them how to expel dissidents. As Garton Ash said to the commission with bitter sarcasm, they 'encouraged the opposition by ignoring the opposition'.
The Polish revolution of 1980 appalled many well-intentioned Germans. 'Solidarity' challenged their programme of encouraging 'change from above', and threatened to upset the Ostpolitik by provoking Soviet intervention and a hardening of Communist regimes. When Jaruzelski carried out his putsch in December 1981, the same Germans felt a surge of guilty relief. A few even congratulated Jaruzelski.
This book has raised a tumult in Germany. Some retort that the Ostpolitik lulled Honecker into such complacency that he failed to see and avoid the 1989 crisis: thus the policy succeeded. (True but dishonest: revolution was exactly what the policy intended to prevent.) Others, especially in the Social Democrat opposition, claim that by recognising the status quo and by resisting the nuclear rearmament of western Europe in the 1980s, they gave Gorbachev the critical confidence to disarm. (I give this more credence than does Garton Ash, who thinks that Cruise and Pershing forced Gorbachev into arms reduction and imperial retreat).
Peter Bender, one of the best Ostpolitik intellectuals, is convincing when he argues that 1989 was only possible because 'Europe' managed to prevent Reagan and Thatcher riding their anti- Communism into a full confrontation with the Soviet Union. But he is wrong when he suggests that Garton Ash's deep love for Poland skews his judgement about Germany. What the author is saying is that ordinary people have a right to rebel - inconveniently, dangerously - and that those who obstruct that right in the name of a 'European peace order' have a tin ear for liberty.
This book is one of the grand, rich works on post-war Germany, to stand on the shelf alongside the books of Alfred Grosser or Waldemar Besson. To me, as a witness of its beginnings, the Ostpolitik - the acceptance of a duty to make Europe at first safe and then free - remains the best foreign policy Germany ever had, for all its blemishes. Of course it was a 'national' policy too; politicians got into the habit of saying 'the European interest' when they meant 'the German interest' until they could scarcely remember the difference. But the difference was not great. As Hans-Dietrich Genscher used to say, 'the more European our foreign policy is, the more national it is'. Or as Garton Ash puts it, German answers to the European question were 'first and last, answers to the German question'.
But what does Genscher's aphorism mean now, when Germany is united? Pessimists suspect it will change emphasis: that only what is good for Germany will be considered good for Europe. Optimists, like me, see a door wide open: a Germany which wants to be restrained and sublimated within a closer European union is the most brilliant international prospect of our times. But if we, the other Europeans, do not go through that door with Germany, it will eventually close.