The BehaviourWorks Australia Method Book provides practitioners with a prioritised list of research and decision-making tools that will increase the chances that any behaviour change efforts will be effective. The Book is based on our extensive experience of applying different behaviour change skills and approaches in partnership with government and industry across a range of contexts. In this Introductory chapter, we outline some of the key benefits of applying the behavioural sciences to influence outcomes related to economic prosperity, better health, social inclusion and environmental sustainability (including specific reference to Covid-19), followed by an overview of the Method. We then describe our plans to release a chapter each month throughout 2021 that focuses on a specific skill or approach (along with a host of complementary resources, including future training and collaboration opportunities). Finally, we describe how we will be applying the behavioural sciences to our author team to deliver the book as planned.