A decade before the 1977 launch, many astronomers and space scientists began their involvement with the Voyager mission through participation in study groups convened by NASA and by the National Academy of Sciences. They came primarily from universities, but also in significant numbers from NASA laboratories, from industry, and from abroad. In 1971 the Outer Planets Grand Tours mission definition group carried out a one-year final study of the mission that was to become Voyager. A competition was held in 1972 to select the Voyager flight instruments and science teams, and a third review stage followed a year later to confirm this selection. Out of this process emerged eleven science investigations, with which more than one hundred scientists were associated. In this chapter we look at the instruments and the persons who designed them for this challenging task. Direct and Remote Measurements The diverse measurements made by Voyager of a planet and its environment can be divided into two broad categories, usually called direct or _in situ_ measurements and remote sensing measurements. A direct measurement involves the analysis of the immediate environment of the spacecraft; remote measurements can be made by analyzing radiation from distant objects. The direct measurement instruments on Voyager measure cosmic ray particles, low energy charged particles, magnetic fields, plasma particles, and plasma waves. Their activity began immediately after launch, monitoring the Earth environment and then interplanetary space until the magnetosphere of Jupiter was reached a few days before the actual flyby. Long after the flybys of Jupiter and Saturn are completed, particles and fields data can continue to be acquired by the Voyagers as they speed outward into previously unexplored regions of space. The remote sensing investigations are essentially astronomical in nature, measuring the light reflected from or emitted by the planet and its satellites. On Voyager, however, these instruments far outstrip their terrestrial counterparts in capability. Primarily, they derive their advantage from their proximity to what they observe—at its closest, Voyager was more than a thousand times nearer to Jupiter than are Earth-based telescopes; and for the still closer satellite encounters, Voyager was nearly ten thousand times nearer than astronomers on Earth. In addition, Voyager provided perspectives, such as views of the night side of Jupiter, that are impossible from Earth. Finally, these instruments could exploit the full spectrum of electromagnetic radiation without concern for the opacity of the terrestrial atmosphere, which restricts ground-based astronomers to certain spectral windows and blocks all observation at other wavelengths.