Sidney Rosenthal was an American chemist who worked for the Binney & Smith Company (makers of Crayola crayons). In the 1950s, he was tasked with creating a new type of writing instrument that could be used on various surfaces, including non-porous ones.
Rosenthal's innovation was the development of a new ink formula that was alcohol-based and could flow easily through a felt tip. This resulted in the first commercially successful felt-tip marker.
The first markers were marketed under the "Magic Marker" brand by Binney & Smith. These markers were an instant success, quickly becoming popular for their versatility and ease of use.
While the exact details of Rosenthal's invention process remain largely unknown, his achievement revolutionized writing and drawing, paving the way for the development of a wide variety of markers we use today.