1969: Society experiences a growing movement toward sexual freedom. Sex outside of marriage is gaining acceptance, at least in part because of the development of the birth control pill. Homosexuality has only recently become legal, and gays continue to suffer society's rejection and hatred.

Today: The sexual freedom fought for in the 1960s has gained widespread acceptance, but concerns about the AIDS virus have caused more people to consider abstinence and monogamy. Gays have made great strides socially and legally but continue to be the victims of discrimination and hate crimes.

1969: Psychiatrist R. D. Laing hypothesizes that madness is a sane reaction to an insane world, and some psychiatrists join him in opposition to traditional treatments for schizophrenia and related disorders.

Today: Scientific research has shown that many mental illnesses are largely caused by biological factors. New and more effective medications revolutionize psychiatry. Success with...