Photoelectric spectrophotometry is used to obtain precise measurements of the equivalent width of the He I x4471 line in Algol as a function of phase of the eclipsing system. Photographic spectrophotometry is used to determine the spectral type of Algol C, which is a companion to the eclipsing pair. From these obser- vations a self-consistent model of the Algol system is constructed which is not unique, but which is in agree- ment with most existing information on the system. This model has three principal features: (1) Algol C is an A-metallic star; the difference in absolute magnitude between stars A and C is 2"'6+ . (2) On star A, the flux in the continuum undergoes a greater limb darkening than that in the helium line; assuming each follows a linear law, the difference in limb-darkening coefficients is 0.4+0.1. (3) Circumstellar helium in the 22P level is present; the spatial distribution of this material is in accord with that expected from theoretical models of mass exchange in binary systems.