The Midwich Cuckoos
by John Wyndham (1957)

Idyllic English village gets visited by a flying saucer and all the women get pregnant. When born the kids are quite good looking, very clever and completely cuckoo. A fine feature film was made in 1960 under the US publication title Village of the Damned. Far and away the creepiest of Wyndham's trio of certifiably classic sci-fi novels.

The High Crusade
by Poul Anderson (1960)

Medieval warfare goes interplanetary when a spaceship lands near the English village of Ansby where the men are preparing to set off on the latest crusade to the Holy Land. The aliens get more than they bargained for while the local knight hatches a grand plan to take advantage of the situation. Better known for his high sci-fi, here Anderson cuts loose and has a bit of fun.

Way Station
by Clifford D Simak (1963)

Simak is famous for espousing simple pastoral values through his wonderfully gentle sci-fi tales. This is the story of a Civil War veteran whose farmhouse is an Earthly 'way station' for alien visitors. While in the farmhouse he does not age. When the local folk get suspicious the authorities close in, potentially threatening galactic peace. Highly recommended.

Roadside Picnic
by Arkady & Boris Strugatsky (1972)

Russia's Strugatsky Brothers were at the zenith of their expressionist phase when they penned this oblique story of aliens who stop-off on Earth for a picnic and trash the place with technological litter. What remains behind is The Zone - a place where men known as Stalkers face madness in search of inter-dimensional rewards. Filmed as Stalker by Andrei Tarkovsky.

Protector
by Larry Niven (1973)

Set early in Niven's Known Space universe, a Pak protector visits Earth to see how the breeding colony is progressing only to find evolution is not going as planned. A 'Belter' (from the asteroid belts) smuggler enters the mix as life's purpose is examined. Niven's hard sci-fi comes to fore with his ramjet fusion drive and gravity polariser. Good, but not essential, Known Space background.

Contact
by Carl Sagan (1985)

Sagan popularised astronomy through an entertaining series of TV documentaries in the early-80s. He followed the success of the Cosmos series with this highly entertaining novel about a series of radio telescopes that pick up some extraterrestrial communication. A hit 1997 feature film starring Jody Foster rekindled interest in the book.

The Uplift War
by David Brin (1987)

Tried and true plot gets top class treatment in the third book of Brin's Uplift series. Patrons of the alien Progenitors make it their business to seed the galaxy and 'uplift' non-intelligent creatures. War threatens when humans develop a bit too fast - already uplifting chimps and dolphins. Works well as a stand-alone, but Sundiver and Startide Rising are also superb.

The Forge of God
by Greg Bear (1987)

When two groups of aliens arrive on Earth it is difficult for humanity to work out who to believe. One promises peace and prosperity, while the other warns that trouble is on the way. While some at the time were disappointed that Bear had apparently moved away from 'high concept' sci-fi, this is undoubtedly one of his best and a popular favourite.