" From his earliest days in school, Lincoln’s comrades remarked upon his phenomenal memory, “the best,” the most “marvelously retentive,” they had ever encountered. His mind seemed “a wonder,” a friend told him, “impressions were easily made upon it and never effaced.” Lincoln told his friend he was mistaken. What appeared a gift, he argued, was, in his case, a developed talent. “I am slow to learn,” he explained, “and slow to forget what I have learned. My mind is like a piece of steel—very hard to scratch anything on it, and almost impossible after you get it there to rub it out. "

― Doris Kearns Goodwin , Leadership: In Turbulent Times