Ben Macintyre, Bloomsbury, £20.00
A Spy Among Friends is a fascinating insight into the life of Kim Philby and the secret world he inhabited. Philby, a high-ranking member of the British intelligence service, was part of the infamous Cambridge Five spy ring.
His defection to the Soviet Union in 1963 stunned the British establishment.
During and after the Second World War Philby was employed by Britain's Secret Intelligence Service (SIS or MI6), but was secretly working for the Russian secret service, which had recruited him in the 1930s.
Macintyre focuses not just on Philby's deceit of SIS, but also of his friends. He does this by telling the parallel stories about his friend and colleague in SIS, Nicholas Elliot.
Philby and Elliot came from similar privileged backgrounds, but whereas Elliot stayed loyal to the British state, Philby threw in his lot with Stalin.
What makes Philby interesting is that he was motivated by political principles. He genuinely believed that by spying for the USSR he was advancing the cause of a fairer and more peaceful world.
Like many of his generation in the 1930s, Philby could see that capitalism was a system based on exploitation and inequality that was dragging the world into economic crisis and war. It was a system that had given birth to the monstrosity of fascism.
But what Macintyre does not make clear is that the Russian state that Philby decided to serve had moved a long way from genuine Marxism. The 1917 Russian Revolution, led by Lenin and the Bolsheviks, was a genuine revolution, with working people exercising power through the soviets - elected councils.
But by the late 1920s any remnants of the gains and democracy of the revolution had been destroyed by Joseph Stalin and the cabal that had usurped power and transformed Russia into a state capitalist tyranny.
Philby's tragedy is that he dedicated his life to a totalitarian state which called itself "socialist", but which was just as exploitative a system as the one in the West.
Perhaps we can understand how in the 1930s Philby could be unaware of the true nature of the USSR, but he stuck loyally by the regime even when its crimes could no longer be ignored, right up to his death in 1988.
In his autobiography, My Silent War, Philby acknowledges that at one point he saw that, "Much was going badly wrong in the Soviet Union", but he decided to "stick it out, in the confident faith that the principles of the Revolution would outlive the aberration of individuals, however enormous".
Although it is fascinating to get a glimpse of the secret world by reading books such as Macintyre's, the real world of the secret services is a nasty one.
They do not just spy on each other, they spy on (and often persecute) dissenting voices within their own countries, and conduct dirty tricks such as the toppling of elected governments. The secret services on both sides of Philby's "silent war" are villains.
But these spooks are not all-powerful. The Tsar's secret police could not stop the 1917 Revolution; neither could the Russian KGB stop the fall of the state capitalist regimes of Russia and Eastern Europe. Even the much heralded MI6 did not foresee the collapse of the "communist" regimes in 1989.