We have built an Anatomically Correct Testbed (ACT) hand with the purpose of understanding the intrinsic biomechanical and control features of the human hands that are critical for achieving robust, versatile, and dexterous movements as well as object and world exploration. By mimicking the underlying mechanics and controls of the human hand in a hardware platform, our goal is to achieve previously unmatched grasping and manipulation capabilities. In this chapter we present distinguishing design philosophy and features of the ACT Hand compared to the existing robotic hands, and the details of the design and assembly of the finger bones, joints, tendons and actuators. We derive and analyze the unique muscle-to-joint relationships, called the moment arms, in the ACT Hand index finger, and present a software architecture for the control of the hand movement and forces by controlling the numerous muscle actuators. We also illustrate the grasping and manipulation abilities of the ACT Hand. The fully functional ACT Hand platform allows us to experiment with novel control algorithms to develop a deeper understanding of human dexterity.keywords Robotic hand Ă Hand biomechanics Ă Human-inspired design Ă Hand control software Ă Moment arm variations