An essay on What Is Quantum Mechanics by Victor Weisskopf as a prologue to the book Discussion of the free electron theory of metals and the basic physics of white dwarf ????cle in a box problem ??on to the classical oscillator Three chapters on the angular momentum problem one of them giving simple recipes ??ng spherical harmonics ????ons of the Schrö??on corresponding to several important problems in quantum mechanics Detailed analysis of the spectra of one and two electron atoms ????on spectra of diatomic molecules ??c resonance experiment ????ons Angular momentum of the photon and the EPR paradox ??al and the Krönig-Penney model ????ons ??ons of Einstein coefficients ????????on