The dynamics of wetting liquids has been related to the dynamics of nonwetting liquids. It appears that the response of wetting liquids form an envelop to the family of responses for liquids with nonzero contact angles. These are singular solutions, and the mathematics of singular solutions has been used to obtain results for the generally less accessible case of wetting liquids from the more accessible nonwetting liquids. Three cases have been analyzed. In the first, the well known Voinov-Hoffman-Tanner rule is derived for a spreading drop of a wetting liquid starting with a known expression for the nonwetting case. In the second, the theoretical results for the blow-off experiments for the nonwetting case have been used to obtain the results for the wetting case, allowing a successful comparison between the theory and experiments. In the third, the solution for drop spreading by Hocking and Rivers [J. Fluid Mech. 121, 425 (1982)] for nonwetting liquids where the lubrication theory approximation is not valid is used to derive the solution for the wetting. The present work appears to be the first in determining the connection between the dynamics of wetting and nonwetting liquids of any kind.