Properly called a Decree of Nullity, it is a finding by a Church tribunal that, on the day vows were exchanged, at least some essential element for a valid marriage was lacking, such as, one of the parties did not intend lifelong fidelity to the other person or excluded having children entirely.
A disputation and arguments about the ends of Marriage is presented as a rebuttal to the approach that procreation is a primary end and that the mutual aid and the remedy of concupiscence is secondary.
The author states his case on it, elaborates on factors affecting it, and posits a worsening scenario should those factors continue to influence the process.
The early Church accepted the Pauline privilege and notions akin to the Catholic annulment. Orthodox have departed from early Christian Tradition on this matter; extensive quotes.
In this article, Edward Peters defends tribunal integrity and refutes any claim of laxity on its part. A Decree of nullity is the actual name of the process used to nullify broken marriages.
Dave Armstrong expresses his interpretation of the differences between annulment and divorce showing that annulment establishes that a marital status never existed whereas divorce terminates a legal status.
Clarence J. Hettinger, after giving a bit of background on annulment, traces the history of change from a paucity of annulements to a comparative avalanche.
