Life on Earth is remarkably dynamic and versatile, as we experience daily in nature: birth, growth, movement, and ultimately death. In this chapter, our aim is to uncover the molecular basis of this dynamism and versatility shared by all life forms on Earth, focusing on protein molecules as the key components that dominate our biological world. Recent experiments using high-pressure NMR spectroscopy reveal that, under physiological conditions, most protein molecules functioning in current biological systems exhibit only marginal stability of their folded structures (N). This marginal stability allows them to fluctuate across their entire conformational space from N to the unfolded space U, encompassing the space in between for the evolutionarily selected “high-energy sub-states” for their specific functions. Although at normal pressures the equilibrium concentrations of high-energy sub-states are too low to be detected spectroscopically, at high pressures their populations are dramatically increased, enabling their detection and structure analyses in atomic detail using advanced NMR techniques. High-pressure NMR spectroscopy has now become an indispensable tool for uncovering the “hidden” dynamic design of protein molecules in nature, which enables their function, folding, interaction, fibrillation, and their roles in adaptation and evolution—fundamental processes for all living creatures on Earth.