{Excerpt} This book is about contract professionals, people such as Ben and Emily who sell their expertise in a market for their services. Contract professionals are mobile workers hired temporarily to apply specific knowledge and skills. Rather than salaries, they receive hourly wages or, less often, project fees. Rather than having employers, contractors have clients, with whom they forge short-term agreements, sometimes through staffing agencies acting as third-party intermediaries in the labor market. Their clients are businesses, large and small; nonprofit institutions; and occasionally individuals seeking specific services. Like Ben, some of the contract professionals whose stories appear on these pages work at a distance from their clients, usually from offices in their homes, where e-mail, fax, and phone can connect them around the globe. Others work mainly at clients' sites of business and, like Emily, may be so integrated into organizational life that they seem indistinguishable from the employees around them. A subgroup of contractors is geographically mobile, relocating periodically as they move from one client site to the next. The contractors who are the subject of this book work in one of two occupational groups: (1) writers and editors or (2) programmers and engineers. In these two occupations, contract employment is well institutionalized, and both contractors and their clients are familiar with its practices. For them, contracting is a relational system that operates in tandem with standard organization-based employment. The system provides staffing options for employers seeking flexibility in the size and composition of a workforce, but it also requires ongoing negotiation with contractors to define the scope and content of each new assignment. For contractors, therefore, informally defined work relations supplant formal affiliation and structural authority in an office hierarchy. Contract professionals must, therefore, depend on their own expertise to enact competence and instill confidence in their abilities.