Complex sentence: In 1971, he was able to induce "Mad" publisher William M. Gaines to appear on "To Tell the Truth" as himself; all four panelists failed to pick out the real Gaines.
Split into simpler sentences: In 1971, he was able to induce "Mad" publisher William M. Gaines to appear on "To Tell the Truth" as himself. However, all four panelists failed to pick out the real Gaines.