For many the law of the Church, canon law, has little meaning; it appears remote both from the Gospel and from the life of most people in the Church. Yet, it can impinge on them at times if a parish priest urges that a baptism be deferred, where a dispensation is needed for marriage or where there is a query about nullity of marriage. Recently, the scandals over clerical sexual abuse of children have drawn wider attention to the need for law also in the Church. At a time when it is popular to assert 'rights' of all sorts ― an identification of authentic rights and of corresponding duties in the Church, as well as mechanisms to ensure that these are respected in practice in a systematic way ― justice and law in the Church cannot be neglected. This book seeks to root the Church's law in the values of the Gospel, in particular in the justice which should guide the lives of those called to follow Christ and in the baptism by which they are incorporated into him and into his Church. The 'canon' or measure of how we should treat one another as members of the People of God and participate in our common mission in the service of that Gospel, according to our particular vocations and functions, is the focus of canon law. No law can replace the Gospel or the Holy Spirit, but canon law is an instrument of justice in the service of the Church and of its mission. The revision of canon law, which led to the Code of Canon Law of 1983 for the Latin Church, sought expressly to reflect the key teachings of the Second Vatican Council. That Code, beyond the general norms for understanding and applying its laws as a whole, centres upon the People of God in our common, diverse and complementary forms of living the Gospel, upon the Church's broad teaching function, and upon its sanctifying function, especially through the sacraments. It attends also to the temporal goods of the Church, for which there are responsibilities of stewardship, to penal law and sanctions and to procedural law ― the latter designed to ensure that practical implementation of the Church's law which is essential if its affirmations concerning justice and mission are not to remain vacuous. This book attempts to provide a theological and juridical introduction and explanation of these various aspects of the Church's life. The schematic presentation of 'key canons' is designed to enable the reader to understand the principal elements of a specific section and to see how those canons can be broken down so that their inter-related parts may be read, analysed and applied. The Code of Canon Law, then, can be seen as a valuable instrument in fulfilling the Church's mission for those with a passion for justice, rooted in the Gospel of Christ.