Book excerpt: This book addresses the issue of trademark use that may be required for the protection and/or maintenance of trademark rights. Since the first edition of this book in 2018, there have been significant modifications in some countries, particularly, following the implementation of EU Directive 2015/2436 in the EU countries. Laws around the world do not attach the same consequence to the lack of use of a trademark, and courts do not always assess in the same way whether a trademark is genuinely used. This is a fundamental issue for trademark owners since, depending on the jurisdiction, lack of genuine use can lead to the refusal of trademark registration, the revocation of trademark rights, or prevent the owner of a non-used trademark from initiating an action based on its trademark. This detailed analysis provides clarity, insight, and guidance on the legal issues and practical implications of genuine use of trademarks in twenty-six jurisdictions worldwide. This book was developed within the framework of the International Association for the Protection of Intellectual Property (AIPPI), a non-affiliated, non-profit organization dedicated to improving and promoting the protection of intellectual property at both national and international levels. This topic was the subject of an AIPPI study, and its subsequent Resolution – The Requirements of Genuine Use of Trademarks for Maintaining Protection (2011, Hyderabad) – which aims to harmonize this issue of genuine use of trademarks. The authors of the chapters for each jurisdiction were carefully selected based on their extensive experience and in-depth knowledge of trademark protection in their respective jurisdictions. Each chapter considers issues and topics such as the following: types of use that qualify as genuine use of a trademark, including requirements as to whether uses are consistent with the function of the trademark or made in the course of trade; requirements as to the volume, duration, and frequency of use; impact of the trademark’s designation of goods and services; issues relating to the sign used, particularly, if it is used in a different form from the registered trademark (this includes consideration of alteration of the distinctive character, or the potential impact of a plurality of registered trademarks for different signs, or the question of use in black and white or in colour); proof to be provided to evidence genuine use as a trademark, including issues of timing and territory; situations in which the issue of genuine use can be of importance; valid reasons for non-use; consequences of lack of use depending on the context, including possible revocation of trademark rights; and case law examples. As a comparative law study and a collection of contributions from around the world on a key issue of trademark law, this book is of tremendous practical interest. Trademark owners, parties involved in or contemplating enforcement proceedings, and interested legal practitioners will benefit greatly from its thorough comparative analysis and guidance. It is also exceptionally valuable as a comprehensive resource for academics and researchers interested in the international harmonization of trademark law.