Hapgood is a play by Tom Stoppard

Tom Stoppard

Sir Tom Stoppard OM, CBE, FRSL is a British playwright, knighted in 1997. He has written prolifically for TV, radio, film and stage, finding prominence with plays such as Arcadia, The Coast of Utopia, Every Good Boy Deserves Favour, Professional Foul, The Real Thing, and Rosencrantz and...

, first produced in 1988. It is mainly about espionage, focusing on a British female spymaster (Hapgood) and her juggling of career and motherhood. The play also makes reference to quantum mechanics

Quantum mechanics

Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...

, including Niels Bohr

Niels Bohr

Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. Bohr mentored and collaborated with many of the top physicists of the century at his institute in...

's "The answer is the question interrogated"; Heisenberg's uncertainty principle

Uncertainty principle

In quantum mechanics, the Heisenberg uncertainty principle states a fundamental limit on the accuracy with which certain pairs of physical properties of a particle, such as position and momentum, can be simultaneously known...

; and the topological problem of the Seven Bridges of Königsberg

Seven Bridges of Königsberg

The Seven Bridges of Königsberg is a historically notable problem in mathematics. Its negative resolution by Leonhard Euler in 1735 laid the foundations of graph theory and prefigured the idea of topology....

.

In the original production in 1988, Felicity Kendal

Felicity Kendal

Felicity Ann Kendal, CBE is an English actor known for her television and stage work.Born in 1946, Kendal spent much of her childhood in India, where her father managed a touring repertory company. First appearing on stage at the age of nine months, Kendal appeared in her first film, Shakespeare...

 played Hapgood and Nigel Hawthorne

Nigel Hawthorne

Sir Nigel Barnard Hawthorne, CBE was an English actor, perhaps best remembered for his role as Sir Humphrey Appleby, the Permanent Secretary in the 1980s sitcom Yes Minister and the Cabinet Secretary in its sequel, Yes, Prime Minister. For this role he won four BAFTA Awards during the 1980s in the...

played her friend and superior Blair. The production was a critical failure, and it was revised significantly in 1994 for the first New York production.