The Recursive Book of Recursion by Al SweigartAn accessible yet rigorous crash course on recursive programming using Python and JavaScript examples. Teaches the basics of recursion, exposes the ways it's often poorly taught, and clarifies the fundamental principles behind all recursive algorithms. It is project-based, containing complete, runnable programs in both Python and JavaScript, and covers several common recursive algorithms for tasks like calculating factorials, producing numbers in the Fibonacci sequence, tree traversal, maze solving, binary search, quicksort and merge sort, Karatsuba multiplication, permutations and combinations, and solving the eight queens problem.