Wave mechanics versus matrix mechanics

Given its focus on Einstein, A. Douglas Stone's book understandably emphasizes the history of wave mechanics and downplays the history of matrix mechanics. Both the Dirac-Jordan statistical transformation theory and von Neumann's Hilbert space formalism, however, grew out of the latter. And it's not just for historical reasons that it's important to give a balanced account of the development of both. It may also affect how we think about and teach quantum mechanics today. One can argue that wave mechanics suggests an interpretation of quantum mechanics in which wave functions or state vectors represent what's real in the quantum world, while matrix mechanics suggests an interpretation in which state vectors represent families of probability distributions over values of observables with the values found upon measurement of the chosen observables representing what's real in the quantum world. If this alignment between different lines of development of quantum mechanics and different interpretations holds up, one's assessment of the relative importance of these lines of development will depend on what kind of interpretation of the theory one prefers.