According to the modal interpretation, the standard mathematical framework of quantum mechanics specifies the physical magnitudes of a system, which have definite values. Probabilities are assigned to the possible values that these magnitudes may adopt. The interpretation is thus concerned with physical properties rather than with measurement results: it is a realistic interpretation (in the sense of scientific realism). One of the notable achievements of this interpretation is that it dissolves the notorious measurement problem.
The papers collected here, together with the introduction and concluding critical appraisal, explain the various forms of the modal interpretation, survey its achievements, and discuss those problems that have yet to be solved.
Audience: Philosophers of science, theoretical physicists, and graduate students in these disciplines.

Lorentz-Invariance in Modal Interpretations.- Locality and Lorentz-Covariance in the Modal Interpretation of Quantum Mechanics.- Valuations on Functionally Closed Sets of Quantum Mechanical Observables and Von Neumann's 'No-Hidden-Variables' Theorem.- The Pros and Cons of the Kochen-Dieks and the Atomic Modal Interpretation.- Projection Operators, Properties, and Idempotent Variables in the Modal Interpretations.- Bohm-Bell Dynamics in the Modal Interpretation.- Discontinuity and Continuity of Definite Properties in the Modal Interpretation.- How Close is "Close Enough".- Decoherence in Bohmian Modal Interpretations.- Quantum Histories in the Modal Interpretation.- Remarks on Unsharp Quantum Observables, Objectification, and Modal Interpretations.- Are 'Sharp Values' of Observables Always Objective Elements of Reality?.- Quantum-Mechanical Self-Measurement.- The Bare Theory and How to Fix It.- Curiouser and Curiouser: A Personal Evaluation of Modal Interpretations.