For Biology 101, Life by David Sadava is amazing. I wasn't even particularly interested in the subject and just needed the course credit, but it was a fascinating page turner and made everything so clear.
I don't know if this counts as a textbook, but Python for the Absolute Beginner is so good for beginning programming. Python is a great language to learn programming with. This book is just so perfectly paced. It's the exercises that make it work so well. It increments the difficulty just a smidgeon with each exercise to gradually get you used to more and more concepts.