More and more tax administrations are setting up specialised units for dealing with large taxpayers. This publication presents the experience of seven Commonwealth country tax administrations that have successfully created specialised departments exclusively to deal with large taxpayers, and identifies good practices in this area. Implementing Large Taxpayer Units highlights the entire process from initial planning through to implementation, in order to identify key factors in success. While the book is primarily meant to assist countries at the start of this process, it will also help administrators who have already implemented such units to identify areas for improvement or to take timely corrective measures.