It is a demanding book -- I never got to really finish reading it cover-to-cover -- but it's very helpful nonetheless even if one reads the parts they find easy

It is a demanding book -- I never got to really finish reading it cover-to-cover -- but it's very helpful nonetheless even if one reads the parts they find easy. For example, the first dozen pages on Calculus have imparted a better understanding of the subject than all the indecipherable (if only due to sheer volume) tomes of Stewart. It was an invaluable boost.