Helped clear a lot of cob webs. Highly recommended for anyone who has used/learned calculus and finds, later in life, a new need or desire to refresh their skills. I think studying Calculus and mathematics in general is akin to exercise. As you exercise to keep your body in shape, I believe you should do mathematics (whether it is required professionally/academically or not) in order to keep your brain in shape.
I was surprised at how many weaknesses this book exposed that I had been so confident in during my youth.