This Practice Note introduces blockchain and distributed ledger technology (DLT) and explains terms such as public blockchain, private blockchain and permissioned blockchain. It considers relevant legal issues such as decentralisation, applicable law, transparency and confidentiality, data protection, cybersecurity, competition law, dispute resolution, taxation and governance. It also looks at the legal status of a distributed or decentralised autonomous organisation (DAO) and examines potential legal issues with initial coin offerings (ICOs).