Direct measurements of cosmic rays

An overview is presented of the scientific implications of direct measurements of cosmic rays in terms of the origins and history of these particles. Within the last several years important constraints have been placed on the possible origins of cosmic rays in the GeV energy range by the analysis of isotopic composition. At higher energies new magnet experiments to measure elemental composition have supported the notion that all nuclei should have similar behaviour with magnetic rigidity. At still higher energies, into the cosmic ray "knee", there are some disagreements between measurements, suggesting that there are various issues which remain to be resolved in this region. We also emphasize the important role played by measurements of spallation-produced nuclei in cosmic-rays. These hold the key to our understanding of cosmic ray source spectra at high energies.