Trustmark Organisations (TMOs) are independent parties which provide e-merchants with trustmarks - a label or visual representation indicating that a product, process, or service conforms to specific quality characteristics. Security, privacy, and business practice are three areas in which trustmarks play an important role. TMOs will issue a trustmark to e-merchants only if they have demonstrated conformity to specific policies regarding security, privacy and business practice. E-merchants hope that, by displaying the trustmark on their websites, e-consumers will trust their certified practice and be more likely to divulge their personal data and transact with them. Past research focuses on economic aspects of trustmarks. This book is the first comprehensive study on trustmarks and related legal aspects. It describes pros and cons of trustmarks for e-economy, e-society and e-policy, assesses TMOs' practice, and focuses on TMOs' liability.