I have used Thomas' Calculus , now what should I consider next (mainly for Differential Equations/Complex Analysis/Fourier Transforms etc.) I heard Kreyzig is good , any recommendations on that ? PS: Actually I found Thomas' to be very good, but when I read Courant's Calculus text, I felt as if I was doing very elementary text. PS2: Oh , and if there's an electronics guy reading this, i am also looking for a text on Basic electronics of transistors. Thx all !