Journey to the Center of the Earth
by Jules Verne (1864)

Typical group of Vernean protagonists - complete with handsome young adventurer and eccentric professor - journey down the core of a volcano to the centre of the earth. They discover various lost world settings where they run into prehistoric monsters and countless dangers - all while espousing solid 19th-century virtues. Timeless.

The Lost World
by Arthur Conan Doyle (1912)

Classic 'lost world' tale follows expedition to an isolated and inaccessible South American plateau where dinosaurs still survive. In the face of popular scepticism, the determined Professor Challenger wants to get back to London to prove his critics wrong. Ostensibly based on the discovery of fossilised footprints near Doyle's home. Still a great read.

Mission of Gravity
by Hal Clement (1953)

Multi-legged alien Mesklinites help a team of humans to recover a vital component from a space probe downed on a heavy gravity planet. Characterisation of decidedly non-human Capt Barlennan as both cultured and capable was atypical for its day. Clement's knowledge of physical parameters made this a 'hard sci-fi' classic.

2001: A Space Odyssey
by Arthur C Clarke (1968)

The now-familiar story of human evolution that culminates in a mission to Saturn to track down the origins of a monolith found on the moon. The super-intelligent HAL 9000 computer starts getting some ideas of his own along the way. Based on the co-written screenplay for the famous Stanley Kubrick feature feature film. A good novel, but rides the film's coattails to a certain degree.

Nova
by Samuel R Delany (1968)

Delany tones down the intellectual stuff in this rip-roaring space adventure that has become minor classic with the cyberpunks. Culturally-refined criminal outcast captain takes his ship and crew on a Grail-quest for the substance Illyrion - which unfortunately can only be found at the heart of a nova. Computer interfacing abounds. Underrated.

Tau Zero
by Poul Anderson (1970)

A spacecraft is designed to travel close to the speed of light, thereby radically slowing the aging of its crew. The brakes fail and it continues to accelerate - allowing eons to pass by in the process. There's another Big Bang at the end of the Universe and the crew has to find a new home. Impressive look at time-travel paradoxes. Anderson's best known sci-fi novel.

Gateway
by Frederik Pohl (1977)

First book in the splendid Heechee Saga and worthy recipient of all three major awards it won. Aliens hideout from 'Assassins' who have little time for any other species. Hoping to get rich quick, humans use their spacecraft in all or nothing missions from the Gateway. Wealthy three-mission veteran has to face what he has become. All-time classic sci-fi.

The Engines of God
by Jack McDevitt (1994)

A rousing archaeological mystery from a topnotch sci-fi writer still in search of a breakthrough. Looking to abandon the ecologically devasted Earth of the early 23rd century scientists aim to terraform the planet Quraqua. An archaeological expedition sets out to discover the secrets of the Monument-Makers before it is too late. Writer on the rise.