In an attempt to identify as many people as possible living in Dublin during the seventeenth and eighteenth centuries, the author has used a wide variety of sources, which he lists at the beginning of the book. The citizens on which he has gathered data are listed alphabetically. The information ranges from as little as "a widow" to as much as a paragraph. If you think you had ancestors who lived in Dublin during this time period, you will want to examine both this book and the original sources it covers.