Efficiency

• The Rise and Fall of Prussia by Sebastian Haffner
  Weidenfeld, 183 pp, £7.95, July 1980, ISBN 0 297 77810 2
• The Northern Crusades: The Baltic and the Catholic Frontier 1100-1525 by Eric Christiansen
  Macmillan, 296 pp, £12.50, May 1980, ISBN 0 333 26243 3

Nations rise and fall: some which were once great no longer are – Sweden, say, or Holland – while Russia, which wasn’t, now is. Sometimes countries – the United States or Israel – arise from nothing. But the subject of Mr Haffner’s book is odder. It first appeared from nowhere and then disappeared quite without trace: to him, a sad disappearance.