In 1967 Landolt-Börnstein published a compilation of nuclear charge radii (Volume 1/2). As a substantial improvement compared with the first publication, the present volume (I/20) contains up-to-date high-accuracy and almost model-independent nuclear charge radii. Results for all investigated isotopes of the elements (Z = 0 up to Z = 96) are given, including the long chains of radioactive isotopes measured by optical spectroscopy. These results have been enabled by a combined analysis of four electromagnetic interactions, namely optical isotope shifts, K X-ray measurements, muonic atoms, and high energy elastic electron scattering, which allows an absolute calibration of the optical measurements.

All experimental data used are listed in the tables, and the steps of the analysis are described in such a way that a new combined analysis can be performed and the nuclear radii reevaluated, as soon as new experimental data might become available.