Like most people I suppose I was more familiar with the von Braun story - from building the V2 with slave labour to chief architect of the Saturn V - and Cadbury devotes a lot of the early book to showing how the two men's different experiences of mid-twentieth century totalitarianism shaped their lives; von Braun successfully surrendered to the Americans with most of his team as the Nazi regime collapsed, Korolev imprisoned in the gulag for a decade. It is interesting that von Braun, rather than Korolev, was hampered by internal political constraints, largely because his face didn't fit and through the late 1950s various arms of the US government tried to find other, more American, engineers who would put stuff in space quicker (and they failed).
Having said that, Korolev had to go right to the top, one dispute between him and Glushko being personally resolved by Krushchev. Korolev was also fortunate in that the failures of his programme could be hushed up. But he seems to have had a lucky touch as well; he took a number of chances with the Soviet space programme, including with the lives of the astronauts, which fortunately succeeded (and intimidated the Americans), and after his death in 1966 the wheels came off - Vladimir Komarov killed on re-entry in 1967, the failure of the N1 rocket, the deaths of the Soyuz 11 crew; all problems that might easily have happened on Korolev's watch but somehow didn't.
Unlike a lot of space histories, this one runs out of steam when we get to the moon landing, having lost the central dynamic of the rivalry between the two chief engineers. But there's plenty to think about anyway.