The first and original Elan was the first production car made by Lotus to use the steel backbone chassis that has since become a trademark of the brand. It was a lightweight car with a fiberglass body paired with a twin cam 1558 cc engine. It had good handling with the help of 4 wheel disc brakes and independent suspension on all 4 wheels.
There was a 4 seat version of the Elan made in 1967. The Elan +2 was sold until the discontinuation of the original model after 1975. This model also had a longer wheelbase to make room for those seats. The original 2 seat Elan would be discontinued 2 years before this car in 1973. The Mazda Miata MX-5 was largely based on the original Elan when it was made in 1990.
The rebirth of the Elan happened in 1989. The M100 Elan was technically superior to most cars of its day. It was controversial because it was front wheel drive and it had a turbocharged Isuzu engine. It was the only Lotus not to be rear wheel drive, and despite testing that showed it handled better than the rear wheel cars, the press seemed to love mocking the few drawbacks that the front wheel drive did have.
The US version of the Elan was slightly modified to pass various safety standards.
Though GM, which owned Lotus at the time, discontinued the Elan after the 1995 model year, Kia would revive the name with the Kia Elan in 1996 and 1997 in the Korean market.
Elans can be found out there on the used market for a steep discount to new price (heck, they're about 2 decades old by now, even older for the originals). The best place to find one is eBay, where you'll also find parts being sold by some very knowledgeable Elan fans.