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Abstract

A variety of high-energy events can take place in the seconds leading up to a
binary neutron-star merger. Mechanisms involving tidal resonances,
electrodynamic interactions, or shocks in mass-loaded wakes have been proposed
as instigators of these precursors. With a view of gravitational-wave and
multimessenger astrophysics more broadly, premerger observations and theory are
reviewed emphasising how gamma-ray precursors and dynamical tides can constrain
the neutron-star equation of state, thermodynamic microphysics, and
evolutionary pathways. Connections to post-merger phenomena, notably gamma-ray
bursts, are discussed together with how magnetic fields, spin and misalignment,
crustal elasticity, and stratification gradients impact observables.