George de Kay, cofounder and president of the independent publishing house M. Evans & Co., died of cancer at his home in Manhattan February 22. He was 76. In 1954 De Kay and Mel Evans founded M. Evans & Co. The two had worked together at Doubleday, where de Kay had been editor-in-chief of Doubleday's first paperback book imprint. M. Evans began as a book packager for larger publishers and grew into a house that published such bestselling authors as Dean Koontz and Eric Van Lustbader. The company's most recent hits have been a series of diet books by Dr. Robert Atkins.