Solastalgia: a word as recent as the feeling it defines. This neologism dating from the early 2000s describes the melancholy that overcomes us when we realize our familiar environment is slowly disappearing. In earlier works, Philippe Dubois reminded readers of how cruelly little they knew of nature and its riches. Here he examines a manifestation of the awareness of environmental emergency. What characterizes this century's new affliction, and how can we recognize it? Dubois gives us the keys to regain control of our environment.