370km (230 miles) E of Piraeus
Kos today is identified with and, at times, nearly consumed by tourism; but the island and its people have endured, and so will you, with a little initiative and independence. Almost three-quarters of the island's working people are directly engaged in tourism, and that tells you something about Kos's beauty and attractions.
Kos has been inhabited for roughly 10,000 years, and for a significant portion of that time, has been both an important center of commerce and a line of defense. Its population in ancient times may have reached 100,000, but today it is less than a third of that number. Across the millennia, the unchallenged favorite son of the island has been Hippocrates, the father of Western medicine, who has left his mark not only on Kos, but also on the world.
The principal attractions of Kos are its antiquities -- most notably the Asklepion -- and its beaches. You can guess which are more swamped in summer. But the taste of most tour groups is thankfully predictable and limited so the congestion can be evaded, if that's your preference.
Kos town is still quite vital. Because the island is small, you can base yourself in the town, in an authentic neighborhood if possible, and venture out from there. You'll get the most out of Kos by following the locals -- especially when it comes to restaurants. If you think you're in a village and see no schools or churches, and no old people, chances are you're in a resort. Kos has many, especially along its coasts.