  This Introduction opens the book {\sl Standing Together in Troubled Times}
which presents a story of friendship between Wolfgang Pauli, one of the
greatest theoretical physicists of the 20th century, and Charlotte Houtermans.
They met at the very onset of the quantum era, in the late 1920s in Germany
where Charlotte was a physics student at G\"ottingen University. At that time
G\"ottingen was right at the heart of groundbreaking developments in physics.
Both Pauli and Houtermans personally knew major participants in the quantum
revolution. Caught between two evils -- German National Socialism and Soviet
Communism -- Charlotte Houtermans would have likely perished if it were not for
the brotherhood of physicists: Niels Bohr, Wolfgang Pauli, Albert Einstein,
James Franck, Max Born, Robert Oppenheimer and many other noted scientists who
tried to save friends and colleagues (either leftist sympathizers or Jews) who
were in mortal danger of becoming entrapped in a simmering pre-WWII Europe.
This book is based on newly discovered documents from the Houtermans family
archive, including Pauli's numerous letters to Houtermans, her correspondence
with other great physicists, her diaries, and interviews with her children.
Almost all documents presented in this book are being published for the first
time.
