Based on people who have maybe used both books, would Tom Apostol's Volume I book be a more preferred book than Stewarts? I'm really aiming to understand everything and not just "know how to do the steps." This is why someone recommended Apostol to me. I am a beginner in Calculus as well, which was a reason why he warned me against Apostol's book as well. I have access to both books at my library so whichever one is the better I will get. If there are any other books, can you recommend them to me as well?