An Able Master
It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils.
From Abel, Niels Henrik, Memoirs de Mathematique, Oslo University Library - Confirming admiration of the work of Simon Laplace, in a note, dated 6 August 1826, scribbled in the margin on page 79 of volume 2 of Abel’s “Paris Notebook” diary.
Abel is now considered one of those “masters,” so quoting him on the subject is fair play. (As proof of this, I need only point out that one of the top-level categories in the standard classification system of mathematical topics is named after him.) Although, I must wonder what it is about mathematicians and the margins of their books.