Many marriages are "ended" by separation or divorce, but for the baptized Christian they remain valid marriages forever. There are, however, cases in which a Christian marriage can be recognized as null, i.e. it never existed. This book, written by a specialist with a gift for clarity on a complicated, sensitive issue, is a guide for a first approach to the problems related to the conditions for eventually declaring the nullity of a canonical Christian marriage. This work is an indispensable aid for the pastors of souls, for Catholic counselors, and can be very useful also for anyone who has serious questions about the validity of his own marriage. The primary purpose of this work is to provide clear, well-founded information in sufficient quantity to parish priests and to all who will act as counselors in these matters, either in formally organized parochial counseling services, or in other possible forms of collaboration with the parish priest, or else in the ecclesiastical tribunals themselves as a step previous to the possible introduction of the case. Among the areas he covers are: Violation of the freedom of consent; Error about a person; Exclusion of offspring; Exclusion of fidelity; Incapacity to consent; Incapacity to assume the essential obligations of marriage; Conditional consent.