Post-disaster reconstruction is a complex process. It requires multi-sectoral involvement, very significant resources and a wide range of skills. For a humanitarian agency the decision to engage in reconstruction and what type of assistance to provide needs to be taken cognisant of the complexities and must recognise the need for expert advice. Lessons from Aceh has been arranged in three key sections: Planning, Design and Construction. The individual chapters provide a checklist of topics. Each chapter begins with a summary of key issues and concludes with key questions that should be considered in future responses. These are illustrated within the main text and boxed case studies by what happened in Aceh and by reference to the Sphere Standards (Sphere, 2004).