The essential role of the valence, residual p‐n interaction in the development of collectivity, though long known in general terms, has recently become increasingly apparent. A brief review of the p‐n interaction is given, including some very basic nuclear data that illustrate its effects and the phenomenological NpNnscheme and the P‐factor. This is followed by a discussion of recent experimental extractions of p‐n matrix elements throughout the periodic table and theoretical efforts to understand them, in terms of both Shell and Nilsson models.