A quantum-mechanical approach is used to study high-momentum-transfer reactions in which a nucleon is knocked out of a target nucleus. It is found that the nuclear interactions of the wave packet produced in such a hard interaction may cancel, so that the nuclear medium is transparent. Expressions for the effective wave-packet--nucleon interaction and the corresponding distorted waves are presented. An analysis of existing ({ital p},{ital pp}) data at beam momenta from about 5 to 12 GeV/{ital c} suggests that only the nucleon and Roper resonance components of the wave packet contribute to the scattering amplitude. The ({ital p},{ital pp}) data and our theory imply that color-transparency effects in the ({ital e},{ital e}{prime}{ital p}) reaction may be significant at relatively low-momentum transfers of {ital Q}{sup 2}{approx}3--6 GeV{sup 2}.