  We report ultraslow group velocities of light in a solid. Light speeds as
slow as 45 m/s were observed, corresponding to a group delay of 66 ms in a 3-mm
thick crystal. Reduction of the group velocity is accomplished by using a sharp
spectral feature in absorption and dispersion, produced by a Raman excited spin
coherence in an optically dense Pr doped Y2SiO5 crystal.
