  We present a new full-potential method to solve the one-body problem, for
example, in the local density approximation. The method uses the augmented
plane waves (APWs) and the generalized muffin-tin orbitals (MTOs) together as
basis sets to represent the eigenfunctions. Since the MTOs can efficiently
describe localized orbitals, e.g, transition metal 3$d$ orbitals, the total
energy convergence with basis size is drastically improved in comparison with
the linearized APW method. Required parameters to specify MTOs are given by
atomic calculations in advance. Thus the robustness, reliability, easy-of-use,
and efficiency at this method can be superior to the linearized APW and MTO
methods. We show how it works in typical examples, Cu, Fe, Li, SrTiO$_3$, and
GaAs.
