To return to the anecdote that opened this work, the goal will be achieved if Nancy Fraser or any other reader can now clearly distinguish ecologism from environmentalism, and feels they have solid points of reference to venture into the vast literature on the subject. This literature is indeed largely made up of publications that address one aspect or another of ecologism, sometimes very remotely; this, without referring to a general framework that would allow the contribution to be situated. Thus, publications on the most diverse subjects follow one another, with nothing to link them. This book aims to escape this kind of forward flight. Ecologism does not have its “Marx” and this is not a coincidence. Its libertarian inspiration pushes it to distance itself from this kind of approach. What emerges is that ecologism is indeed a separate political ideology, not currently merging with socialism, liberalism, or conservatism. And, contrary to easy criticism, the coefficient of adversity increases as one gets closer to conservatism.