Hi, I am taking (ordinary) differential equations as a summer course and we are studying from a horrid textbook, in my opinion. Just curious if anyone might be able to suggest what is considered to be the "standard" introductory text on ODE. While I'm certainly interested in PDE, I don't believe I'll take it as a university course, probably will study that on my own accord, thus a book concerned only with ODE is fine provided it is thorough and detailed with regard to the theory. (That said, if there is some monstrous text that covers everything DE and is amazing, I would look into purchasing it.) I know Courant and Apostol get thrown around a lot as reccomendations for Calculus so I was wondering if there anything along those lines with regard to ODE.