Man has created the ultimate machine...Colossus. The President of the United States is only too happy to make the announcement: ""I have to tell you, the people of the world, that, as of eight o'clock Eastern Standard Time this morning, the defense of the Nation, and with it the defense of the free world, has been the responsibility of a machine."" ""Defense"" is the key word and Colossus is so intricately set up that once started ""no human being can touch Colossus"" let alone turn it off. Professor Charles Forbin, its creator, finds that his nightmarish apprehensions about certain unforseen side effects prove only too true, particularly after it is discovered that the Russians have developed a close relative to Colossus, the Guardian. And that the machines are capable of free thought...and threats. It's a case of man reduced to impotency, a slave to the ""busy self-import and chatter of the teletype."" A big subject handled with precision and assurance.