Any way you stack it, Adecco is the world's largest employment agency, serving some 100,000 clients from more than 5,500 offices worldwide. The company primarily provides temporary staffing services, but Adecco also offers permanent employee placement, project assistance, outsourcing, and other human resources-related services. Besides its core industrial and office staffing services, Adecco maintains six professional lines: Engineering & Technical; Finance & Legal; Human Capital Solutions; Information Technology; Medical & Scientific; and Sales, Marketing & Events. Adecco traces its roots to 1957 and has a history of growing through mergers and acquisitions.