[eigenvector]

That may well be true in your discipline, but there are some excellent, concise texts in undergraduate mathematics. For example, Apostol's Calculus or Spivak's Calculus on Manifolds. Not the most accessible texts by a longshot, but not your average Pearson or Wiley drivel either.

[rckrd]

Adding on to eigenvector's point, there's a certain beauty in a self-contained mathematics textbook.

[catshirt]

likewise, the explanation for how the concepts flow together. drawing these connections is usually the last step for me in the "a-ha" moment, and too few resources explain the connections between concepts really well. khan academy being a strong exception.