AbstractTime‐of‐flight mass spectrometers are able to cover mass ranges to around a half a million Da. The mass resolution of these instruments has been improved drastically by incorporation of electrostatic mirrors. The ion‐optical solutions enabling these achievements and other promising features are discussed in terms of: First‐ and second‐order space focusing in time for linear drift time‐of‐flight mass spectrometers; velocity focusing by time lag; ion‐packet bunching in post‐source impulse focusing; first‐ and second‐order energy focusing in time, in single‐ and double‐stage homogeneous electrostatic mirrors with normal and oblique ion incidence; gridless designs; perfect time focusing in parabolic potential and axial symmetry; cylindrical ion mirrors and toroidal electrostatic deflectors as time‐of‐flight mass analyzers; three electrostatic sector geometry applied in secondary ion microscopy and four toroidal sector systems for tandem mass spectrometry; poloidal electrostatic sectors. Estimation of time‐of‐flight mass spectrometer performance limits is discussed and the stable as well as the metastable peak shapes found in time‐of‐flight mass spectra.