Fermat’s and Twain’s notes have inserted readers into a different historical context. They allowed them to step into the exact moment a spark of genius hit those guys. Besides taking part in the original inspiration for future remarkable works, readers were able to join their way of thinking.

Such an intimate view of their inner world will enrich your library and help you understand what may have planted a posterior thought.

Marginalia should spark sympathy, recollections, and sometimes even disagreement. If it creates emotion and that emotion is passed on, even as a momentary reminiscence or reconsideration of one’s ideas, it did its job.