The "Emperor of the Known Universe", Shaddam IV, feared the growing power and influence of House Atreides over the other Great Houses and worried that Duke Leto of House Atreides would become a dangerous threat to his rule. The Duke's war masters were building a military force that was the equal of the Emperor's own elite fighters, the Sardaukar.

The Emperor decides to reignite an old conflict between House Atreides and their bitter enemies, House Harkonnen who governed a desert planet called Arrakis (also known as "Dune"). To achieve this, the Emperor grants the fiefdom of Dune to House Atreides whilst plotting with House Harkonnen to help them retake the planet later and wipe out the Atreides with the help of his Sardaukar troops.

The reason why the desert planet Dune is regarded as so important is that it is the only planet known to produce the "Spice Melange" - a special narcotic substance that allows the Navigators of the Spacing Guild to fold space & time for Interstellar Travel.

The fly in the ointment for the Emperor's plan is the main protagonist of the saga, Paul Atreides, the son of Duke Leto. Paul proves to be the prophesized "Kwisatz Haderach" a special human being with enough mental power to develop prescience and see into the future. Furthermore, his mother (Jessica) is a member of the Bene Gesserit sisterhood whose members train their bodies and minds through years of physical and mental conditioning to obtain superhuman powers and abilities which Paul adopts.

After the defeat of House Atreides at the hands of the Harkonnens and the Sardaukar, Paul and Jessica are forced to flee into the desert. There he befriends the indigenous people of Dune, the Fremen, and takes the name "Muad'Dib" (after a nimble desert mouse) which ingratiates him with the desert people. Paul is destined to rise to religious leadership amongst the Fremen thanks to his shrewd military strategy in leading the campaign of resistance against Harkonnen rule and his special Bene Gesserit fighting powers which he teaches to the desert people.

This is an approximate and incomplete background to the climactic confrontation between the Freman, the Harkonnens and Shaddam IV's forces, and Paul's ascension to becoming the new emperor. Dune has a reputation for being a hard read and it's almost impossible to provide a concise summary because of the many layers of complexity it has. David Lynch's quirky 1984 film bravely took on the epic tale only to fail by having too much of it left on the cutting room floor despite being two and a quarter hours long! You just can't shoehorn this book into a single movie. Denis Villeneuve is faring better by splitting it into two parts but I imagine that the lack of contextual information and background in the first film makes the story less accessible and understandable for those who have not read the book beforehand.

Dune has almost as much of a high-fantasy feeling as well as science fiction. This is reinforced by the fact that there are no computers or robots in the Dune universe which is something that appears very strange in our information technology-obsessed age with visions of a technological future. Thousands of years before the events of the book, there was an intergalactic war between humans and artificial intelligence. Even though the humans won, computers were banned throughout the empire. Instead, all calculations are now carried out by a special breed of humans called "Mentat" who are highly skilled in logic, computing and cognitive thinking.

The story is not completely fantastical, however, devoid of any grounding in science. The world-building is superb and the desert planet "Dune", and how the native Fremen people have learned to deal with its extreme conditions, is very convincing. For example, the "stillsuit" they wear is designed to preserve the body's moisture and filter out impurities so that drinkable water is circulated to catch-pockets. This permits the wearer to survive for weeks in the open desert. Much like their smaller counterparts on Earth, the giant sandworms in Dune are attracted to regular vibrations on the surface. To avoid attracting any sandworms the desert people have learned the "sandwalk" that will not create a rhythm. Conversely, if it is desirable to summon a sandworm then a "thumper" is used. This is a short stake with a spring-loaded clapper on one end which pounds repeatedly.

Rich complexity, wonderful character development and convincing worldbuilding all combine to make a story with such gravity and substance that I consider it to be the best science-fiction novel I have ever read. In fact, nothing else can get close. If you were to only ever read one other science-fiction book in your life, make this it.