Sinposis

ON ALBERT EINSTEIN'S SEVENTY-SIXTH AND FINAL BIRTHDAY, A FRIEND GAVE HIM A SIMPLE TOY MADE FROM A BROOMSTICK, A BRASS BALL ATTACHED TO A LENGTH OF STRING, AND A WEAK SPRING. EINSTEIN WAS DELIGHTED: THE TOY WORKED ON A PRINCIPLE HE HAD CONCEIVED FIFTY YEARS EARLIER WHEN HE WAS WORKING ON HIS REVOLUTIONARY THEORY OF GRAVITY--A PRINCIPLE WHOSE IMPLICATIONS ARE STILL CONFOUNDING PHYSICISTS TODAY.