This thesis is an assessment of the legal career of Philip Yorke, first Earl of Hardwicke from his admission as a student of the Middle Temple in 1708, until his retirement as Lord Chancellor, in 1756. Its emphasis is on 'his work in the Chancery, the basis of his judicial reputation. It is a legal biography, an essay in judicial technique. Hardwicke's early years and education,both before and after admission by his Inn, are considered in the first chapter, as background to his later career. The second chapter contains an account of Hardwicke's years at the bar, including his work, private and official, after his appointment as Solicitor-General, and subsequently as Attorney-General. Both the nature and extent of his practice are considered. Comment is made on Hardwicke as a writer and law reporter. The third chapter assesses Hardwicke's work as Lord Chief Justice of the King's Bench, with reference to a number of important cases decided during his few years as a judge of that Court. particular reference.is made to his judgment in a leading case on whether ecclesiastical canons bound the laity. Hardwicke's appointment as Lord Chancellor and his general views on the nature of the Chancery jurisdiction are considered in chapter four; in particular his views on, and use of,judicial precedent in the Chancery. In the course of so doing his administration of the Chancery jurisdiction in relation to fraud, infancy, lunacy and married women is considered. So also is Hardwicke' s use of maxims in equity, and his relationship with the common law courts, their judges, and the House of Lords. Chapters five to eight are an examination and assessment ' of Hardwicke's treatment of trusts. The nature, creation and classification of trusts is first considered, followed by his approach to the construction of trusts and the extent to which he used them as a tool for gaining Chancery jurisdiction. As an aspect of this, the distinction between executed and executory trusts and the effect of precatory words is considered. The remainder of these chapters is concerned with particular aspects of doctrine, trusts and powers, trusts to preserve contingent remainders, trusts of long terms and charitable trusts, including the application of the Mortmain Act 1736. The final chapter deals with the position of trustees, their capacity and the manner in which Hardwicke interpreted their duties and liabilities. The subject of mortgages is considered in chapter nine, with particular reference to Hardwicke's views in relation to the nature of the equity of redemption and the doctrine of tacking. Finally, it is concluded that although Hardwicke was clearly a 'great' lawyer of considerable talent he was extremely conservative and not particularly imaginative or innovative despite the opportunity provided by his talents and long term as Chancellor. His contribution was as a systematiser and expositor of equity, only.