Last year I took ap calculus ab, and im taking ap calculus bc next year. So i decided to refresh my memory this summer and went through The Calculus Lifesaver by Adrian Banner, and thoroughly enjoyed it since i didn't get the depth that it went into in class. Now i know there are more "in depth" books out there, specifically Apostol and Spivak. I read what I could of them online, which was only like a couple of pages, and liked Apostol's approach a little better, but could someone lead me towards which one will give me a true understanding of calculus? I love a challenge, there would defiantly have to be problems-solutions, good explanations of proofs, theorems, defiantly have to cover calculus AB and BC, and really overall just give me that true mathematical understanding I'm looking for. Thanks in advance.