These were big creatures with one eye.
The three original Cyclopes Arges (thunderbolt), Brontes (thunder) and Steropes (lightning) were born from Gaea and Uranus.
They were described as enormous giants, big as mountains, with a single eye under a bushy eyebrow with heavy hammers. Their number was not named.
Uranus imprisoned them into Tartarus because he was scared they would dethrone him.
In other versions he send them to Etna where their roar caused volcanic eruptions. Gaea and Cronus conspired to bring down Uranus.
Uranus was cast off from rule and the Cyclopes were freed although Cronus cast them back into Tartarus when he felt threatened.
They were freed again after the Titan battle of 10 years after which Zeus came to power. They fought on the side of Zeus.
They became the servants of Zeus out of gratefulness and they made the lightning bolts for him.
For his brother Poseidon they made the trident and for his son Perseus the helmet that could make invisible.
For the goddess huntress Artemis they made a silver bow, quiver and arrows in Cretan-style at Sicily. Also a bronze helmet for Hades was made.
They were skilled workers.
Apollo killed the cyclops, or all of them, who had made the thunderbolt with which Zeus had killed Apollo’s son Asclepius.
The Cyclopes assisted Hephaestus in his forge at Etna. Hephaestus and the Cyclopes forged the shield of Achilles.
At Lemnos the Cyclopes were replaced by the Cabeiri.
In the story of Heracles he encounters walls at the city of Tiryns that the Cyclopes have built. Also the citadel is hinted to be built by Cyclopes.
Proetus returned to Argos where he fought Acrisius for the throne backened by seven Cyclopes among other things.
There was no clear winner and the brothers split the kingdom. Proetus put the Cyclopes to work in the port of Tiryns, hewing stone to form impregnable defences.
Perseus, grandson of Acrisius, enlisted the Cyclopes to built the massive walls of a stony outcrop of Mycenae.
Also the Lion Gate of Mycenae is said to built by Cyclopes.
Polyphemus was a cyclops and the son of Poseidon.
Odysseus met the cyclops Polyphemus (Garrulous) during his travels on an island of Cyclopes.
These lived in isolated communities without laws or decision-making assemblies. They also did not honour guest friendship (the Greek concept Xenia).
These kind of Cyclopes were more nasty and ill-mannered then the earlier Cyclopes. They lived in isolated existence in caverns.
Odysseus went into a cave with twelve men and feasted on the cheese. Then Polyphemus came back and rolled a boulder in front of the entrance.
Polyphemus kept Odysseus and two of his companions prisoner on their return journey from Troy in order to devour them. He had devoured some of the Greek.
Odysseus made the cyclops drunk. When it asked for Odysseus’ name he said his name was nobody.
Then Odysseus blinded his eye with a burning torch. The other Cyclopes asked what was going on. Polyphemus then said nobody was hurting him.
They escaped by binding themselves under the bellies of the sheep of Polyphemus.
Before this Polyphemus had fallen in love with the Nereid Galatea. Galatea preferred the shepherd Acis. Polyphemus crushed Acis beneath a rock out of jealousy.
Acis was changed by the gods into a river.