The {eta}'(958) meson has been studied in the reaction K{sup -}p {yields} {Lambda}{eta}', with K{sup -} beam momenta ranging from 1.70 to 2.65 Gev/c. The Dalitz plots of {eta}' decay into {pi}{sup +}{pi}{sup -}{eta} and {pi}{sup +}{pi}{sup -}{gamma} have been examined, and from them we have determined that the most likely quantum numbers of the {eta}' are I{sup G}J{sup P} = 0{sup +}0{sup -}, although J{sup P} = 2{sup -} cannot be completely ruled out. They have also shown that the decay into {pi}{sup +}{sup -}{gamma} is mediated by the decay {eta}' {yields} {rho}{sup o}{gamma}. An examination of the production process has yielded further evidence for the J{sup P} = 0{sup -} assignment and suggested that the process takes place via K*(891) exchange in the t channel. Branching fractions and cross sections have been determined, and finally a search for a negatively charged {eta}' in the deuterium reaction K{sup -}d {yields} p{Lambda}{eta}' has confirmed the I = 0 assignment for the {eta}'.