“As Mary delivered what was to be her last lecture about the Galapagos Islands, she would be stopped mid-sentence for five seconds by a doubt which, if expressed in words, might have come out something like this: "Maybe I'm just a crazy lady who had wandered off the street and into this classroom and started explaining the mysteries of life to these people. And they believe me, although I am utterly mistaken about simply everything."She had to wonder, too, about all the supposedly great teachers of the past, who, although their brains were healthy, had turned out to be as wrong as Roy about what was really going on.”