[not published: supplied by author] Although the implied contractual duty of employees to serve with fidelity and good faith has long been recognised, its origins have been unclear. It is usually dated from a series of cases in the late nineteenth century. It has been contended that this duty is really a transmogrified form of fiduciary duty. This article shows that the duty of fidelity is not only considerably older than usually recognised, but has been formulated by the courts in a consistent manner and relying exclusively on contract principles. Recent decisions which distinguish contractual and fiduciary obligations are not only well-founded in history and doctrine, but reflect the common law’s abiding recognition of legitimate interests of both employer and employee.