Hand dexterity is the hallmark of human skill and intelligence. From Pablo Casals’ sublime cello playing to the mundane task of tying one’s shoelace, the level of dexterity in humans stands out among our primate relatives. How we achieve such seamless skill is still a mystery. How to repair them once lost after neurological injury remains a formidable challenge. In this talk, I will first present findings from our recent longitudinal study on acute stroke recovery. Using behavioral and lesion analyses, we show that largely separable biological systems support fine finger control and strength, as well as their recovery. This finding suggests that hand dexterity needs to be targeted separately for rehabilitation. I will then discuss our recent effort in designing sensitive tools and tasks for assessing and rehabilitating hand dexterity. Lastly, I will discuss our initial attempt to gain a comprehensive understanding of hand dexterity by directly comparing two major traditional paradigms of dexterity: finger individuation and precision grip.