Abstract: This dissertation is an exploration of what underpins and informs clinical nursing practice by telephone in mental health emergency settings. A critical review of the literature provides the foundation for discussion. Points of reflection explore links between the literature and the author's own experience and thoughts about clinical practice. Findings are presented within three main sections. 'Historical Context' considers the development and function of mental health emergency service telephone work. Practical aspects are discussed under `Service Provision Context.' 'Nursing Context' explores the fundamental skills involved in clinical reasoning and the preparation of staff for telephone work. Whilst 'Best practice' in the area of nursing by telephone is yet to be well defined, this work aims to provide a foundation for further inquiry, research and dialogue.