The authors' nearly complete redshift survey of the galaxy cluster A1142 includes 63 new redshifts. In the 2-sq deg survey region only about 60% of the galaxies brighter than mv = 16.5 are cluster members. The foreground/background contamination gives the illusion of substructure in the galaxy distribution. After isolating and removing this contamination, the authors derive a mass-to-light ratio for A1142 of M/Lv = 410 M_sun;/L_sun; or M/LB(0) = 520 M_sun;/L_sun; (H0 = 100 km s-1 Mpc-1). This result is consistent with the values for other well-studied systems of galaxies.