Ideas and Opinions presents the famed theoretical physicist Albert Einstein's observations on the development of his academic discipline and also his views on such diverse social topics as freedom, religion, education, politics, government, pacifism, disarmament, the fate of the Jewish people, Nazi Germany, and the likelihood of nuclear holocaust.

When writing about he humanities, Einstein is modest about his fame but happy to share his views on disarmament, art and science, and the abuse invited by wealth. Technology gives people enough material security to develop their personalities. Following orders does not cancel responsibility for evil. Everyone should be free to develop intellectually and artistically. Religion must concentrate on moral action. When science and religion respect one another's boundaries, no conflict is possible. Moralizing in school is useless; pupils are motivated by a love of truth.

The Great Depression as a crisis differs from earlier ones because unchecked technology has created massive unemployment; interwar disarmament is essential in the face of mechanized warfare; and later, atomic weaponry intensifies the danger. Two world wars have dangerously militarized America. Security through superior military power is a disastrous illusion. Peaceful cooperation is a must, realized by eliminating fear and distrust, renouncing violence, and empowering supranational bodies to decide security questions.

Einstein with his own Jewishness, sees Zionism not as a political movement but a realization of the social ideal of the Bible, a seat of modern intellectual life, and a spiritual center for all Jews. Judaism is not creedal, but Jewish life has a characteristic stamp. As World War II approaches, Jews know that they suffer for a sacred cause. The land of Kant and Goethe must recover from the Nazi "distemper". Germans are collectively responsible for electing Hitler and must never again be able to threaten humanity.

The final half of the book, "Contributions to Science", discusses the relations between empirical facts and general laws, the nature of theoretical physicists, and the theory of relativity as a two-story building—the "special theory", applying to all physical phenomena except gravitation, and the "general theory", which rests on the special theory. The special theory of relativity recognizes the physical equivalence of all inertial systems, and space and time merge to produce four dimensions just as rigid and absolute as Newton's space. Contemporaries spend twenty vain years searching for a uniform interpretation of the "quantum character" of systems and phenomena. Quantum mechanics has seized a good deal of the truth and will be a touchstone for a future theoretical basis but not the starting point for it. As Lessing says, "The search for truth is more precious than its possession".