Underwater cultural heritage (UCH) is integral to both cultural heritage and natural heritage, thus making it a shared Ocean Heritage. The stories of our societies and our ancestors are wrapped in intangible connections with the ocean and preserved on the seafloor as artefacts, shipwrecks, and remains of those lost or buried at sea. Deep sea mining (DSM) threatens this Ocean Heritage and has the potential to destroy crucial pieces of our past and disrupt our deep cultural connections to the ocean. This book is designed to highlight the potential threat of DSM, covered here mostly in international waters and as regulated by the International Seabed Authority (ISA), and make ocean professionals across many different fields aware of those dangers and of the work is being done to help mitigate the possible launch of DSM operations. It does not aim to be the final word on the issue but rather start a discussion and encourage scientists and cultural leaders to engage and work together.