is beautiful" hypothesis. Increasingly, he sees industrial activity as being performed within international networks of organizations led by large firms. Some of these networks involve simple vertical relationships in which large firms subcontract less advanced technological functions to smaller firms. The "Lean" part of the title reflects the recent tendency of many large firms to pare down by subcontracting to smaller firms functions they previously performed themselves. Other networks Harrison considers, such as Silicon Valley and the Italian industrial districts, involve horizontal as well as vertical relations among innovative small firms. Harrison sees these networks as increasingly being coordinated by large firms through various types of alliances and ownership relations. In Harrison's world, the large firms are the key drivers of technological change. The "Mean" part of the title reflects Harrison's portrayal of small firms. He depicts them as increasingly the repository of society's economic dregs the low-skilled, poorly paid, and transiently employed. Advocates of small firms, on the other hand, perceive small firms as an important source of vitality in developed countries. They argue that in many industries, small firms are more efficient at innovation than large firms. Consistent with this, they contend that in recent years the preponderance of new jobs in developed economies have