This eleventh edition was developed during the encyclopaedia's transition from a British to an American publication. Some of its articles were written by the best-known scholars of the time and it is considered to be a landmark encyclopaedia for scholarship and literary style.

This book presents the legislation that formed the basis of Roman law - The Laws of the Twelve Tables. These laws, formally promulgated in 449 BC, consolidated earlier traditions and established enduring rights and duties of Roman citizens. The Tables were created in response to agitation by the plebeian class, who had previously been excluded from the higher benefits of the Republic. Despite previously being unwritten and exclusively interpreted by upper-class priests, the Tables became highly regarded and formed the basis of Roman law for a thousand years. This comprehensive sequence of definitions of private rights and procedures, although highly specific and diverse, provided a foundation for the enduring legal system of the Roman Empire.