Christian Moral Principles--The Way of the Lord Jesus by Germain Grisez--in 3 volumes.
Volume One of Germain Grisez's 3-volume work is constructed primarily as a textbook in fundamental moral theology for students in Catholic seminaries. However, those already ordained to the priesthood, teachers of religion, parents concerned about the catechetical formation of their children, and others will find this book helpful as well. Some questions naturally arise regarding this monumental undertaking. Why, for example, should so extensive a project be carried out in one field -- that of moral theology? And why should seminary students devote so much of their time to this one subject? The answer is that morality is characteristic of human actions whose free and intelligent choice make human beings like unto God. This volume specifically covers the fundamentals of Christian moral principles.
The second volume in the series, Living a Christian Life, deals with the responsibilities common to all Christians.
And the Third Volume, Difficult Moral Questions, seeks to provide guidance, if not always answers, to some 200 intriguing problems that Christians grapple with each day.