Book excerpt: Tables of vertical cutoff rigidities calculated using the trajectory-tracing technique are given for two epochs of the geomagnetic field. The Finch and Leaton magnetic field coefficients were used for Epoch 1955, and the Jensen and Cain coefficients were used for Epoch 1960. Each table includes the geographic coordinates and L value of each location together with the main cone cutoff rigidity, the Stormer cutoff rigidity, and the effective cutoff rigidity. Data for approximately 2900 locations on the earth are presented.