The story of the ages of man can be found in Hesiod's Works and Days, translated by Hugh G. Evelyn-White, between the verses 109 and 210, starting with the verse 106 after previously talking about the story of Prometheus, the Theft of godly fire and creation of Pandora which consequently brought mischief among other bad things to the mortals. Hesiod believes that mischief is the reason why his brother Perses is holding back from work and rather bribes the corrupt judges to get the easy wealth from his brother. And at the end of the story, in verse 105, he says that there is no way to escape the will of Zeus who punished both Prometheus and mankind for the deceit. In verse 106 it is evident that Hesiod wants to hold on to that last thought, where there is no escape to the will of Zeus, when preparing to tell the story of the ages of man.
When the deathless gods created the golden race of men, it was a time of prosperity and peace that allowed all living beings to live in harmony, to be happy and in love. It is said that in this age animals could speak with human voice and no one would grow old or get ill. Together, they lived in abundance of everything and even when their time was over, the death came during sleep without any pain. This time was placed during the ruleage of the Titans where Cronus was a leader, after dethroning his father Uranus. But instead of living in peace, Cronus, after hearing the prophecy of being overthrown by one of his children, went and ate five of his children when they were born, except for Zeus who later came and set his brothers and sisters free. They then rebelled against their father and it all escalated to a ten-year war, called Titanomachy, which more or less ended the golden age in destruction.
When the golden age had ended, the golden race still existed and roamed the earth as benevolent spirits. The war, where the Olympians had won, was over and peace was achieved. It was time for the gods to create a new, silver, generation of mankind. This silver race was said to be inferior in all terms to the golden race. They were immature and needed a hundred years to grow up. But when they finally grew up, they lived short lives because of their foolishness to keep sinning and not listening and honoring the gods who were losing patience and at some point Zeus became so mad that he destroyed this silver race of beings and ended the sliver age.
Beings of silver age were sent to the underworld and became known as the blessed spirits of Hades. Zeus was again bored and decided to make a third generation, called the brazen race of men. These bronze men were strong and warlike, had weapons and armour of bronze and even houses of bronze. They worshipped the destructive works of Ares and, instead of bread, ate hearts of fellow men. In the end they were consumed by their own rage, destroying each other, and were sent to the underworld for eternity, never to see the light again.
According to Theogony of the Apollodorus' Bibliotheca, the Bronze age was ended by the Deluge or the Great flood, set up by Zeus for being disappointed and outraged by the aggressive and cannibalistic behaviour of the bronze race.
After the bronze age Zeus created another race, an honorable race of heroes, who were noble and respected the gods. Among them were also individuals with divine qualities, called demi-gods. Most of them died in wars such as Trojan war and Seven against Thebes. The souls of those, who passed away, went to a special place called the Elysian Fields or the Islands of the Blessed, somewhere in the Underworld, surrounded by deep-swirling Oceanus. It was a place where the souls would remain forever and live a blessed and happy life in the same role they had enjoyed in life. It is also said that Zeus eventually promoted his father Cronus, from the depths of Tartarus, to become a ruler of the souls of these righteous and significant people.
And finally, Zeus created the last race of man, called the iron race, where Hesiod puts himself in. It is a time of constant stress and labour. Morality is gone and men are constantly opposing each other, lying and seeding mistrust. It is a time where humans grow old quickly and are constantly beset by troubles and pressures. At the peak of this age people will no longer feel shame or regret at wrongdoing and there will be no help against evil. Mankind will be forsaken by the Gods and Goddesses and Zeus is set to return one day to destroy this race, just like he had done it in the past.