I often see textbook recommendations here that about rigour and depth of coverage. Serious books for serious people! This question is different. I'm looking textbooks that inspire a love for mathematics. And I want to come at it from two different angles: (1) is there a textbook that was so good, led to such beautiful insights that it was almost a religious experience and cemented your decision to be a student of mathematics? (2) What textbooks would you recommend a casual, self-studying, student of math, that keeps them motivated and inspired to keep moving forward? Assumptions: student has a day job and only so much time to devote ideal texts have a big payoff/effort ratio (possibly sacrificing some depth in the process) inspires love and interest in the subject not discouraging, in the sense of a punishing difficulty level (we all know texts that are viewed as a right of passage!) The form forced me to choose a prefix but please feel free to respond about any math topic/level you like! A friend recommended this one: https://www.amazon.com/Visual-Complex-Analysis-Tristan-Needham/dp/0198534469 He said it is full of diagrams and graphs and is incredibly clear.