"The Joy of X" by Steven Strogatz "Euler's Gem" by Dave Richeson "A Companion to Analysis" by Tom Körner "Elementary Number Theory: A Problem Oriented Approa

"The Joy of X" by Steven Strogatz "Euler's Gem" by Dave Richeson "A Companion to Analysis" by Tom Körner "Elementary Number Theory: A Problem Oriented Approach" by Joe Roberts