  We generalize the classical Bass model of innovation diffusion to include a
new class of agents --- Luddites --- that oppose the spread of innovation. Our
model also incorporates ignorants, susceptibles, and adopters. When an ignorant
and a susceptible meet, the former is converted to a susceptible at a given
rate, while a susceptible spontaneously adopts the innovation at a constant
rate. In response to the \emph{rate} of adoption, an ignorant may become a
Luddite and permanently reject the innovation. Instead of reaching complete
adoption, the final state generally consists of a population of Luddites,
ignorants, and adopters. The evolution of this system is investigated
analytically and by stochastic simulations. We determine the stationary
distribution of adopters, the time needed to reach the final state, and the
influence of the network topology on the innovation spread. Our model exhibits
an important dichotomy: when the rate of adoption is low, an innovation spreads
slowly but widely; in contrast, when the adoption rate is high, the innovation
spreads rapidly but the extent of the adoption is severely limited by Luddites.
