20) J.T. M'Intosh, World Out Of Mind, 1953
An alien hostile takeover of Earth is planned by placing 50,000 espionage agents in strategically important positions, including the President of the United States. It goes where you expect it to, taking a hundred pages to warm up after which the action is over in the next sixty-five, with a final battle of Independence Day proportions condensed to just ten pages. Two curious aspects: the world population takes voluntary intelligence tests, with the lowest level coded Brown and the highest White – I hope this wasn't intentionally racist – also in that nine years after publication in 1953, the events depicted in the closing chapters uncannily resemble the Cuban Missile Crisis of 1962.