Globular proteins, which act as enzymes, are a key component of the network of life. Over many decades, much experimental data has been accumulated yet theoretical progress has been somewhat limited. We argue that the key results accumulated over the years inexorably lead to a unified framework for understanding proteins. Our framework yields predictions on the existence of a fixed menu of folds determined by geometry, the role of the amino acid sequence in selecting the native state structure from this menu and the propensity for amyloid formation. The experimental data and our new approach reveal an astonishing simplicity underlying the protein problem.