As mentioned, the Númenóreans were the descendants of the Edain, the Elf-friends of the First Age. As a reward for their services during the War of Wrath, they were given the grand island of Númenor as their abiding place. They also received longer life (200 years average), greater height, and greater wisdom.
Númenor, which had been raised up by Ulmo, Vala of the seas, was shaped like a star upon the ocean, and was in between Aman and Middle-earth. These Edain reached the island in the year 32 S.A.. Elros, the brother of Elrond, was their first king.
From the start, the friendship of the Númenóreans was between the Dúnedain of the West and the Eldar of Eressëa. The white swan ships of those Eldar brought many gifts to the Númenóreans: birds, trees, herbs, and more. Unfortunately, as time progressed, the kings of Numenor began to envy the Eldar for their immortality, and a fear of death infected the island. Later on, kings fell dead, decrepit and witless, as they hopelessly clung to their lives. Thus faded the bliss of the Númenóreans, if not their power. They had sailed the earth to the East, using their mighty wooden ships, and even glimpsed from their tall ship prows the Gates of Morning, in the eastern continent. They founded many colonies in Mortal Lands, north and south, and there they ruled. With the gradual creation of a colonial empire, the pride of the Kings grew. The old customs were, for the most part abandoned, those that were kept were kept out of fear of the Valar. Most of the Númenóreans distanced themselves from the Eldar, and towards the end they persecuted any who were in fellowship with them. The 25th King, and also the last, Ar-Pharazôn, was made angry by the reemerging Sauron in Mordor. The King sent a vast army, so large and imposing that Sauron found himself deserted by his own armies, not a single large battle fought. But what Sauron could not crush with his armies, he would manipulate with cunning mind and honeyed-tongue. He prostrated himself before Pharazôn, and was taken prisoner. In less than three years, the Dark Lord had gone from top-priority prisoner to the King's greatest councilor. All save one (Lord Amandil of Andúnië) of the Royal Council fawned on Sauron. After many years, the king felt the shadow of death near, and Sauron, ever the opportunist, seized his chance. He told the aging king of "The Giver of Freedom and Life" Melkor, behind closed doors. The king, desperate to escape death, turned to the worship of the Dark. At Sauron's urging, a great temple was built, and the tree Nimloth was cut down, though not before Isildur, Amandil's grandson, escaped with a fruit of the tree. In the year 3310 SA, Sauron urged Pharazôn to take what the king desired for so long, the immortality of Aman. In 9 years, a vast fleet was made ready, and Pharazôn, almost wavering, boarded his flagship, Alcarondas, and set sail. 39 days later, Numenor met with apocalypse. The king had landed at Aman, and the Valar had ceded guardianship of Arda to Eru. Eru tore Aman away from the world, and formed the flat disc of Arda into a globe. Númenor was flooded, and its proud towers and walls crumbled. Sauron was taken unawares, and his last fair form was destroyed, and "as a gale" he escaped. Not all the Númenóreans were killed, however. Nine ships, led by Elendil son of Amandil escaped to the North of Middle-earth, and there founded the kingdoms of Gondor and Arnor. The race of Black Númenórean colonists existed far away in Harad still, as well as the rest of the Númenóreans' colonies. Thus ended Númenor, the Land of Star.