The preface to the first edition of this book described basement extensions as a “novel and specialist type of construction” which, at that time, was confined to extremely affluent areas of London. Since then, basement extensions have become more common and are found all over England and Wales. Despite their increasing popularity, basement extensions remain a complex and specialist type of construction with many difficult and knotty problems. This book provides a clear explanation of the law related to those problems, including ownership of the subsoil, restrictive covenants, rights of support, underground water rights, planning control and building regulations, as well as claims for private and statutory nuisance. This book also explains the law relating to liability for defective underpinning and foundations, which is a frequent arena of disputes as second basement extensions become more common. This book has been complied by one of the leading legal experts on basement extensions from their extensive experience acting for both developers and adjoining owners. It is essential reading for all lawyers, surveyors, engineers, architects and other professionals involved in the construction of basement extensions.