The Swiss physicist Wolfgang Pauli (1900-58) descends from a notable Jewish family of publishers and booksellers in Prague. This essay presents biographical data and Prague fortunes of his father, grandfather and great grandfather. The roots of friendship between Wolfgang Pauli's father and the family of Ernst Mach, then a professor at the University of Prague, are documented and a hypothesis is suggested concerning the motives that induced Wolf Pascheles, Wolfgang Pauli's father, to choose the name 'Pauli' as his new surname.