SERVICES INNOVATION: COMING OF AGE IN THE KNOWLEDGE- BASED ECONOMY IAN MILES Services: Seen but not Heard? Received 10 January 2000 Revised 8 May 2000 Accepted 8 May 2000 International Journal of Innovation Management Vol. 4, No. 4 (December 2000) pp. 371–389 © Imperial College Press 371 1 Bell (1973); Fuchs (1968; 1969); Greenfield (1966). 372 I. Miles 2 Gershuny and Miles (1983). Services Innovation: Coming of Age in Knowledge-Based Economy 373