  The annihilation-creation operators of the harmonic oscillator, the basic and
most important tools in quantum physics, are generalised to most solvable
quantum mechanical systems of single degree of freedom including the so-called
`discrete' quantum mechanics. They admit exact Heisenberg operator solution. We
present unified definition of the annihilation-creation operators (a^{(\pm)})
as the positive/negative frequency parts of the exact Heisenberg operator
solution.
