Cardiac biophysics rests on three fundamental pillars: energy production, electrical excitation, and mechanical work. Studies of cardiac metabolism, bioelectricity, and biomechanics have been very productive at all levels of reduced complexity, but especially at the levels of tissue, cell, and molecule. The three cardiac biophysical pillars work in concert and cannot be fully understood in isolation. However, available experimental methods are limited, restricting our ability to study them simultaneously.