SPICE is a high resolution imaging spectrometer for the Solar Orbiter mission, observing in extreme ultraviolet wavelength bands 70.4 – 79.0 nm and 97.3 - 104.9 nm. The instrument has been built by an international consortium led by STFC Rutherford Appleton Laboratory. We summarise the instrument performance and describe how SPICE will address the key science goals of Solar Orbiter by providing the diagnostics of the physical state and composition of the plasmas in the solar atmosphere, in particular investigating the source regions of the solar wind outflows and ejection processes which link the solar surface and corona to the heliosphere. SPICE spectra include lines from elements such as H, C, N, O, Ne, Si, Mg, S, Ar and Fe. By observing intensities of selected lines and line profiles, SPICE will derive temperature, emission measure, flow velocity and elemental abundances for the plasmas in the temperature range from 10,000 K to 10MK. Several bright lines in the SPICE range permit high-cadence observations of plasma dynamics in the upper chromosphere and the lower transition region to study flows, oscillations and transient brightening events. We also identify intensity ratios of elements with a low First Ionization Potential (FIP) to high-FIP elements, suitable for creating maps of low/high FIP abundance ratios and establishing connectivity to in-situ observations. SPICE can also study the coronal heating, and contribute to studies of transient ionization and non-equilibrium processes in the transition region.