  The inspiral phase of gravitational waves emitted by spinless compact binary
systems is derived through the fourth-and-a-half post-Newtonian (4.5PN) order
beyond quadrupole radiation, and the leading amplitude mode ($\ell$, m) = (2,
2) is obtained at 4PN order. We also provide the radiated flux, as well as the
phase in the stationary phase approximation. Rough numerical estimates for the
contribution of each PN order are provided for typical systems observed by
current and future gravitational wave detectors.
