There are two main theories as to who invented the Reuben sandwich, both of which involve the name Reuben. One theory is that the sandwich was first made at a New York City restaurant called Reuben's Delicatessen sometime around 1914. Another theory holds that the sandwich was made and named for a man named Reuben Kulakofsky, who frequently dined at the Blackstone Hotel in Omaha, Nebraska.
The latter story was researched and published by Elizabeth Weil, the granddaughter of the chef at the Blackstone Hotel, a man named Bernard Schimmel. According to Weil's story, her grandfather was an educated and trained chef who decided to dress up a simple request for a corned beef sandwich with sauerkraut when a regular customer, Reuben Kulakofsky, ordered it at some point in the 1920s. Schimmel apparently mixed the sauerkraut with Thousand Island dressing, added Swiss cheese and grilled the sandwich as a reflection of his advanced culinary skills.