Paul A. Samuelson,  one of the most influential scholars of economics, died Sunday at the age of 94. Samuelson was on the faculty at the Massachusetts Institute of Technology, and was credited with leading the department's rise  to become one of the most influential in economics. He won the Nobel Memorial Prize in Economics in 1970, and the Nobel Foundation's Web site  maintains information on his accomplishments and his Nobel lecture. For generations of undergraduates, his textbook Economics  was their introduction to the field. The textbook was first published in 1948 and Samuelson's name remains on it, even as in recent years William D. Nordhaus, a Yale economist, became the primary author. The 19th edition was recently issued by McGraw-Hill. Paul Krugman, an economist at Princeton University who formerly taught at MIT, and shared an office suite with Samuelson, wrote the following  in The New York Times Sunday of his former colleague: "It's hard to convey the full extent of Samuelson’s greatness. Most economists would love to have written even one seminal paper -- a paper that fundamentally changes the way people think about some issue. Samuelson wrote dozens: from international trade to finance to growth theory to speculation to well, just about everything, underlying much of what we know is a key Samuelson paper that set the agenda for generations of scholars."