  Second quantization is an essential topic in senior undergraduate and
postgraduate level Quantum Mechanics course. However, it seems that there is a
lack of transparent and natural derivation of this formalism from the
first-quantization one in most existing textbooks. Without introducing the
concept of a simple harmonic oscillator and taking the case of an assembly of
identical fermions as an example, we provide a less ad hoc derivation of the
second quantization formalism based on the equivalence of the fully
antisymmetric many-fermion states and the Fock states.
