This paper builds on Teece's, 1986 paper to consider how appropriability conditions affect the ability of an industry, and the economy as a whole, to progress. In particular, it offers a careful discussion of the broader costs and benefits of patenting. Can too much appropriability actually work against the broader interests of society in fostering economic growth and technical advance in the market? (c) 2006 Elsevier B.V. All rights reserved.