Rob Becker’s hilariously insightful play about the ways that men and women struggle to relate, has both sexes roaring with laughter and recognition. DEFENDING THE CAVEMAN, written by and starring Mr. Becker, opened on Broadway in March 1995, ran two and one-half years, played 671 performances, and entered the record books as the longest-running solo play in Broadway history. It is an outrageously funny and surprisingly sweet exploration of the gender gap. -vn