A fellow named Conrad Hubert founded the American Electrical Novelty and Manufacturing Company in 1896. We don’t know much more about Conrad from those early days, except he was born in Russia, emigrated to America, and launched the pioneering days of battery flashlights.
However, our personality for today did not actually invent the idea. He purchased U.S. Patent No. 617,592 from one David Misell in 1899, instead.

The Ever Ready Days of Battery Flashlights
Conrad founded the American Electrical Novelty and Manufacturing Company three years before he purchased the patent. And so it was not long before he launched his pioneering days of battery flashlights based on David Misell’s idea.
The design was as revolutionary as it was simple. Put three D-size batteries front-to-back in a tube, with a light bulb up front. Add a brass reflector behind the bulb, a switch in the middle, and a cap at the rear end to complete the circuit. This may seem simple to us, but it was way ahead of its time!

Conrad renamed his company The American Ever Ready Company in 1905. He continued selling flashlights and batteries and his business kept on growing. We know the company as Energizer nowadays. The EverReady trademark is just a distant memory from the past.
More Information
Inspiration Behind Your Battery Flashlight
Vacuum Tube Batteries in Bygone Times