The Sum of All Fears is the best-selling thriller novel by Tom Clancy, and part of the Jack Ryan series. It was the fourth book of the series and was also later turned into a film. v 1973, during the Yom Kippur War; at its height the Israelis opt for a tactical nuclear strike, but this was changed at the last minute. Unfortunately, one Mark 12 nuclear weapon was not yet removed from an Israeli attack aircraft—piloted by Motti Zadin. That aircraft was shot down and crashed into mountains in Syria, and the nuclear weapon was lost (an empty quiver).