My last contact with chemistry was over 20 years ago, and I wanted to get across the basics for a masters course I'm doing on medicinal chemistry. This book is perfect: starts from the ground up and moves onto advanced topics later in the book. What I like the most is that compared to other books I browsed, when it explains the basics in terms that are easily understood, it never talks down to you. It's also very readable, with good analogies throughout to explain what's going on in "common sense" terms, and frequent examples of how the concepts relate to biological systems.