Do you have a hobby or an interest? Maybe a collection? Me too. As a kid it was baseball cards, stamps, coins and beer cans for me. I still have a bunch in a closet upstairs. At any rate, many of us have some semblance of an interest in something be it a sport, a collection, history, etc.
People on the autism spectrum have interests too. In the early days, my son was fascinated by spinning wheels and water. Something right out of the autism brochure you'd pull from the doctor's office. I remember when he was 2 he sat on the driveway and pulled a washcloth out of bucket of water and suds for close to an hour while I washed the car. He sat so still and was so amazed by what he saw. I wish I could see the wonder in simple things like that.
I've met people on the autism spectrum with all sorts of deep interests like hairless dogs, the Simpsons, or particular movies and movie characters! The desire to focus, the ability to memorize all the details and the skill to focus so deeply, and often for so long at a stretch, on these topics is really amazing. With all of our multi-tasking at home and at work, I can't help but want to emulate them. Their deep interests are the antithesis of Attention Deficit Disorder.
Interestingly, my son doesn't have really deep interests. I describe him as a skipping stone along a smooth lake. Interests come and go. Novelty is what drives him. There are recurring themes but he moves from one to another relatively quickly. What's the same between my son and many others on the autism spectrum is that for the short stints, his interest is almost all consuming. The last 2 days it's been a notebook with notes on the tricks he's learning on his razor scooter. Before that it was bottlecap pins made by taping safety pins to beer bottle caps.
I love the deep interests. I love when parents and friends support those interests. I crave for the ability to focus in a similar manner. Every once and a while I'd like to be something other than 'Master of many and expert of none'.