This guide provides an introduction to expert witness evidence in Ireland and is aimed at both lawyers and potential expert witnesses. The topics covered include an overview of the Irish legal system: both civil and criminal, different types of quasi-judicial tribunals, and arbitration/mediation procedures. It explains who can be an expert witness, the scope of evidence given by expert witnesses, and the function and duty of expert witnesses. A key part of the book examines the role of the expert in a pre-trial context, including report writing, as well as the expert giving evidence in court. The book then examines experts in various contexts, e.g. commercial court, criminal trial, medical experts, engineering experts, in a local authority context, and family law.