"On a new derivation of Birkhoff's strong ergodic hypothesis he once remarked in exasperation: "To be any more immaculate they will have to begin sterilizing the paper as well as the theorem !""

"... he gave a seminar in Oxford about his ideas on liquid helium, but on this occasion even the theorists were baffled. Onsager's final comment in reply to a question was: "The results are not bad when you consider the enormity of the swindle which I have perpetrated!""

"Of the electroencephalogram he once remarked: "It is like trying to discover how the telephone system works by measuring the fluctuations in the electric power used by the telephone company.""

"There's a time to soar like an eagle and a time to burrow like a worm. It takes a pretty sharp cookie to know when to shed the feathers and (long pause) to begin munching the humus! (characteristic Onsager giggle)."

"There are a lot of folks, some quite talented, who arm themselves with methods and then go hunting for vulnerable problems; but to accept a problem on its own terms and then forge your own weapon--now that's real class!"

"They made the mistake there of assigning Onsager to the basic Chemistry I, II course. He just couldn't think at the level of a freshman. Frankly, he was fired. I won't say he was the world's worst lecturer, but he was certainly in contention. He was difficult to understand anyway, but he also had the habit of lecturing when his back was to the students and he was writing on the blackboard. To compound matters, he was a big man, and students had to peer round him just to try and see what was being written."

"In the days of Kepler and Galileo, it was fashionable to announce a new scientific result through the circulation of a cryptogram which gave its author priority and his colleagues headaches. Onsager is one of the few moderns who operates in this tradition."

"... a reluctance to publish anything except fully-polished work, combined with the habit of dropping valuable hints couched in gnomic terms. The obscurity of his utterances is not due to a desire to mislead; rather it is a result of an inability to appreciate the limitations of his hearers. To those who have been able to appreciate what he tries to say, he has been a source of deep stimulation."

"He had been warned that non-theoreticians would be present and that he should phrase his talk in not too technical language. He plunged, nevertheless, into the mathematics of spinor algebras. After about twenty minutes, one of the many experimentalists in the audience had the courage to ask him what a spinor was. Onsager replied, thoughtfully: "A spinor--no, a set of spinors--is a set of matrices isomorphic to the orthogonal group." With that he gave the famous Onsager grin, twinkled his Nordic blue eyes at the bewildered faces around him, and continued the lecture as if nothing had happened."

"Onsager regarded chess, so he said, as too much like real problem-solving to spend much time on it. When he wanted to unwind from his work he would play solitaire, and bridge was a good relaxation in company."

"... when asked by Longworth how he would explain the electrophoretic effect in "physical terms," he picked up Longsworth, chair and all, and carried him across the room."

"One day Onsager told him he had decided to try an experiment on the separation of isotopes by thermal diffussion. "Fine," said Kraus, and was doubly pleased when Lars told him that the only equipment he would need was a long tube. But his encouragement was quickly withdrawn when Onsager explained that the tube must be made of platinum and would have to stretch from the basement to the third floor of the chemistry building. Kraus never pestered him again about doing an experiment, which "was too bad," writes Julian Gibbs, "because no one succeeded in conducting this experiment until more than a decade later, when it was needed as part of the Manhattan Project for the atomic bomb.""

"Pauli judging the World War II period in physics wrote in a letter to Casimir: “Nothing much of interest has happened except for Onsager’s exact solution of the Two-Dimensional Ising Model.”"

"In 1944, E. Onsager produced, quite unexpectedly, an exact evaluation of the partition function of the model in two dimensions. It was a real tour de force. I had studied his paper in Chicago in the spring of 1947, but did not understand the method, which was very, very complicated, with many algebraic somersaults... I was thus led to a long calculation, the longest in my career. Full of local, tactical tricks, the calculation proceeded by twists and turns. There were many obstructions. But always, after a few days, a new trick was somehow found that pointed to a new path... after about six months of work off and on, all the pieces suddenly fitted together, producing miraculous cancellations, and I was staring at the amazingly simple final result[, the spontaneous magnetization of the ising model.]"