PART I

THE QUANTUM

‘Briefly summarized, what I did can be described as simply an act of desperation.’

—MAX PLANCK

‘It was as if the ground had been pulled out from under one, with no firm foundation to be seen anywhere, upon which one could have built.’

—ALBERT EINSTEIN

‘For those who are not shocked when they first come across quantum theory cannot possibly have understood it.’

—NIELS BOHR