Chapter 1 offers an overview of the book and summarizes the state and trends in climate change legislation. Making use of a unique global database, Climate Change Laws of the World, the chapter identifies over 1,200 climate change laws and policies of similar stature in the 164 countries the data covers. This stock of laws is the result of over 20 years of policy making and speaks to the growing attention that legislators are devoting to climate change. In 1997, at the time the Kyoto Protocol was signed, there were only about 60 relevant laws and policies. Countries use different routes to address climate change. In some countries the primary avenue is acts of parliament, that is, formal laws passed by the legislative branch. In others, the policy direction is defined through executive orders, decrees and strategies. Climate change laws also differ in scope and ambition. Some laws are specifically focused on climate change, advancing explicitly emissions reduction or adaptation targets. Others introduce climate concerns into sector policies, such as those on energy, or broader development plans. Understanding these different approaches becomes increasingly important as countries implement their pledges under the Paris Agreement.