Footfall: Larry Niven and Jerry Pournelle

When the object headed toward Earth from the vicinity of Saturn was detected, the immediate reaction of the USA and the USSR was one of suspicion but this soon gave way to the astonished realisation that the impossible was happening - Earth was about to receive visitors from a distant star. And surely they hadn't travelled for centuries just to be hostile - they must be friendly. A welcoming party was assembled and sent to an orbiting space station This was catastrophically wrong. Once in range the alien spacecraft launched a debilitating attack on the space station and took the bulk of the welcoming party prisoner. Missiles launched at it were destroyed with ease, and a single nuclear detonation in the upper atmosphere emitted an electronic pulse that played havoc with telecommunications on the ground. Earth was at their mercy. They could bombard the Earth with with pinpoint-accurate lasers and small meteors that struck with the force of nuclear explosions - and all this without using their major weapon, one they mysteriously called The Foot...Cover art by Tony Roberts.