the hand truck, one of the simplest of all tools. As a matter of fact, it's a Class One Lever. That's some physics 101.

 
The Hand Truck 360 and Attachit Strap were designed and patented by Richard Cortese. 

Richard had to transfer 4’X 8’ sheets of plywood from the storage shed to the garage. Cortese had to hand-carry each individual sheet of plywood out of the storage shed, through the gate, along the side of the house, and finally into the garage.

Cortese, an industrial designer, did some research and found that all hand trucks have wheels that only go forward and backward. So, he designed and patented the versatile Hand Truck 360. By using triggers at hand level, it glides safely in any direction. It seems simple when you realize a library sliding ladder does this. 

After he received his patent, Cortese enlisted the help of his cousin, Judy Kochevar to help with the business side of things and The Hand Truck Company, LLC was founded.

History of the hand truck/dolly:

Some time in the 16th or 17th century, someone had to put kids to work, because way back then, there were no public grade schools, there were no child labor laws, and kids had to get a job to help earn some income to cover their cost to their parents, because there was no birth control devices and people were making kids from about puberty to the grave. And, there was a LOT of international trade now that shipping across the oceans was happening.

But kids are usually unable to do heavy labor, because they aren't strong, so, someone attached two wheels together made a hand truck so young boys could move large sacks of spices and other light cargo, because they were unable to lift the large sacks by hand. By using hand trucks they were able to work as well as grown men in moving items around factories, warehouses, and piers. 

https://www.thehandtruckcompany.com/about

https://en.wikipedia.org/wiki/Hand_truck

https://www.linkedin.com/pulse/industrial-vintage-trolley-craig-bell

Why do we commonly call a hand truck a Dolly? No one knows. I looked, all over the internet, and it's just one of those things. One theory is that it's a slang term derived from Trolley. 

The first use of a two wheel truck or hand truck, was before the era known for steam locomotive travel, but the train era probably expanded the dolly's mainstream acceptance throughout civilization. 

Porters used the hand trucks with two wheels at the end of a metal frame to load and transport baggage. As the industrial revolution progressed these carts continued to show up as new forms of transportation, they became the norm, and are still in use today as baggage carts at airports. The cart/trolley dates back to the Chinese Sui Dynasty (581-618) where art shows carts pulled by bulls.

https://www.wholesaleutilitycarts.com/blog/history-of-carts/

https://www.douglasequipment.com/blog/what-is-the-difference-between-a-dolly-hand-truck-and-a-folding-hand-truck/