You can Google EVOO and read on Wikipedia for hours about EVOO.
Quality EVOO is the product of pressed olives: basically pure fruit oil.
Easy to digest.
Much of what is sold as EVOO is processed, cooked,refined oil. You might as well use Canola.
Trader Joes has some good EVOO. You can find good EVOO at most Health Food stores.
The refined light olive oils aren't much if any better for you than Canola.
I use first press EVOO for all my cooking except for deep frying and then I use Peanut oil.