Well, as Prof Weyl says, it's a Riemann Surface he wants to talk to you about. Now that's saying a lot. Just remember people like Schrodinger and Einstein had people like Weyl and Grossman teach them about such surfaces. So it's not for the faint hearted (my heart and mind caved in to look elsewhere)
I have many reservations reading stuff that good Prof has put out. First is his very old fashioned symbolism. Extremely Archaic and looks like a cross between Arabic and Gothic. Its quite nonsensical to use all those gothic stuff and bold to the point where you are distracted from learning and trying to comprehend fonts!
Point two is prepare the following before you can even come within sniffing distance of the book.
1. Calculus and Analysis (Start (and end) with Courant and John Vol 1)
2. Complex Analysis (Try the cheap Richard Silverman edition by Dover)
3. Differential Equations (Ordinary and Partial)
4. Open this book.....and best of luck poring all those symbols only Weyl enjoyed using. Even the great Pauli found his symbols "thick as lipstick that one has to rub away before one can understand it"
If this appears too much, leave it out of your cart. Better still, look elsewhere (If you are getting Da Carmo prepare yourself knowing a lot of Algebra of the Saunders MacLane kind)