Book excerpt: Mental, neurological and substance use (MNS) disorders are highly prevalent, accounting for a substantial burden of disease and disability globally. In order to bridge the gap between available resources and the significant need for services, the World Health Organization launched the Mental Health Gap Action Programme (mhGAP). The objective of mhGAP is to scale-up care and services using evidence-based interventions for prevention and management of priority MNS conditions. The mhGAP Intervention Guide version 1.0 for MNS disorders for non-specialist health settings was developed in 2010 as a simple technical tool to allow for integrated management of priority MNS conditions using protocols for clinical decision-making. With uptake in over 90 countries, mhGAP-IG 1.0 version has had widespread success. It is our pleasure to present mhGAP version 2.0, with updates incorporating new evidence-based guidance, enhanced usability, and new sections to expand its use by both health care providers as well as programme managers. It is our hope that this guide will continue to provide the road-map to deliver care and services for people with MNS disorders around the world and lead us closer to achieving the goal of universal health coverage.