Book excerpt: How should we interpret our ancestors' decisions to marry in a particular form or place, or at a particular time? Did their choices make them exceptional or normal for their day? Might their marriages have been bigamous, clandestine, or void? Or might they have conscientiously followed the rules set down by Church and State? Since its publication in 2012, Marriage Law for Genealogists has become the indispensable guide for everyone tracing the marriages of their English and Welsh ancestors between 1600 and the twentieth century. Based upon years of painstaking primary research and studies of thousands of couples, it explains clearly and concisely why, how, when and where people in past centuries married. Family historians just starting out will find advice on where 'missing' marriages are most likely to be found, while those who are already well advanced in tracing their family tree will be able to interpret their discoveries to better understand their ancestors' motivations. Rebecca Probert is Professor of Law at Warwick University and the leading authority on the history of the marriage laws of England and Wales, a subject on which she has written extensively.