Although some chemical company operations have almost always been outsourced, the recent push among chemical companies to concentrate on their "core competencies" has led to new outsourcing arrangements. This month's Cover Story recounts the history of chemical company outsourcing, describing its rationale and identifying the activities within chemical companies and their plant operations that are being outsourced. The article also provides a general methodology for evaluating whether to outsource certain activities and reveals key elements of successful outsourcing programs.