The chemist Linus Pauling was one of the few recipients of two Nobel Prizes, the Chemistry Prize in 1954 and the Peace Prize in 1962. He was also the only person so far receiving two Nobel Prizes without having any co-recipients. When the Peace Prize was announced, however, some thought that he should have shared it with his wife. She had initiated his activities for nuclear disarmament and always backed him up during his protest marches. Pauling came to Lindau four times and gave four lectures. Two of the lectures concerned his disputed thesis that very large intakes of vitamin C could act as a treatment against cancer. It seems that these two lectures were not recorded, possibly because Pauling thought that the subject was too controversial. The other two lectures have chemistry titles but are, interestingly enough, more than chemistry lectures. Actually, the present 1983 lecture has an extended introduction where Pauling talks about nuclear weapons and world peace. It seems that he once made the decision always to say something on this subject when he gave a lecture. In his characteristically loud and clear voice, he argues in a logical way that the two major players, the US and the USSR, should agree on diminishing their stocks of nuclear warheads. At the time, they represented about 3-5000 times more explosive power than the bombs which exploded during the whole of World War II. According to Pauling, if this amount was to be blown up, the result could cause the extinction of the human race, similar to the extinction of the dinosaurs 60 million years ago! But eventually Pauling turns to the subject of chemistry and tells an interesting story, which began in 1930, when he got an idea about the structure of the bonds formed by a carbon atom, thereby introducing the so-called tetrahedral carbon atom. In his lecture, Pauling reports on the application of this idea to the bonds formed by transition metals and comes to analogous conclusions.