In this paper we argue that Long Wave Theory provides a useful conceptual tool for understanding the transition from the industrial to the, post-industrial economy. While economic theories struggle to fully explain the structural changes involved in the shift towards the information economy, long wave theory offers a promising avenue for understanding the complex relationship between technology and economic development. However, a central aspect of long wave theory-the key factor-is still ambiguously dealt with in the theory and in need of further refinement. We argue that the role of the key factor in long wave theory goes beyond providing economic signals in a technological system as contended by some proponents of long wave theory. Only ...