Published in 2015, WMO Guidelines on Multi-hazard Impact-based Forecast and Warning Services (WMO-No. 1150) caught the crest of a wave of interest in Impact-based Forecast and Warning Services (IBFWS) and quickly became a standard reference text for those developing forecasting and warning services. This new addition to the Guidelines, Part II – Putting Multi-hazard IBFWS into Practice, is intended to be authoritative and useful. It is certainly not dogmatic or exhaustive. IBFWS is a rapidly evolving field and the additional chapters here should be considered as reflecting and complementing the growing body of literature on IBFWS, emanating from WMO such as the HiWeather project The Future of Forecasts: Impact-based Forecasting for Early Action, the 2020 guide published by the International Federation of Red Cross and Red Crescent Societies (IFRC). In addition to these Guidelines, a wealth of additional material, including many more case studies and information and training resources, is available on a companion web page at the WMO website. Globally, we are still in the very early stages of implementing IBFWS, and there is still much benefit to be offered, especially to the most vulnerable communities in the world, through continuing the work of applying the concepts of IBFWS and strengthening them wherever possible. The team of experts who assembled these Guidelines hope that they can make some contribution to this progress.