"Riemann's style is extremely difficult. His tragically brief life was too occupied with mathematical creativity for him to devote himself to elegant exposition or to... polished presentation... Riemann's best ideas have been incorporated in later, more readable works. Nonetheless... No secondary source can duplicate Riemann's insight. Riemann was so far ahead of his time that it was 30 years before anyone could begin really to grasp his ideas... [T]he results which Siegel found in private papers were a major contribution to the field... in 1932, seventy years after Riemann discovered them. Any simplification, paraphrasing, or reworking... runs the risk of missing an important idea, of obscuring a point of view which was a source of Riemann's insight, or of introducing new technicalities or side issues which are not of real concern. There is no mathematician... whom I would trust to revise his work."