Having directly observed one of the most rapidly spreading global pandemics, we understand more than ever the power of contagion. In today’s interconnected world, trends originating in one corner, whether it’s a disease, clothing fashion, or an online social media challenge, can swiftly gain momentum on the opposite side of the globe, often within a matter of days or even hours. This rapid diffusion is enabled by our globalised world and developments in technology and ICT. Social networks and social influence are strong influencers in shaping our attitudes and behaviour. However, this influence can be a double-edged sword. On the one hand, it brings people and cultures together, it facilitates the exchange of information and resources. On the other hand, it can be easily exploited to spread misinformation and exert pressure on individuals to engage in negative behaviours like smoking or violence. This phenomenon is commonly referred to as ‘social contagion.’ In this handbook you can find the result of ENRGISED: Engaging Residents in green energy investments through social networks, complexity and design. In 2019 we saw an impasse in the Dutch energy transition, where many technologies were available but not many people were taking action. Since then, global events, such as Covid 19 and the invasion of Ukraine, have disrupted our world and the energy market. In the midst of these changes we conducted our research. Between 2020 and 2023, we studied the use of social contagion - social influence and the effect of social networks - towards the energy transition in neighbourhoods in the Netherlands.@en