In light of the “global society of extinction”—a term that reflects the dire trajectory of humanity’s ecological footprint and its profound implications for our present—there is an urgent need to reevaluate our relationships with other living entities. This book proposes a new ontological paradigm of coexistence, termed “becoming-into-others” (BIO), which delves into themes of life transformation, extinction, symbiosis, and becoming-with. It aims to explore, analyze, and bolster arguments in favor of innovative cohabitation methods with the diverse inhabitants of Earth. As the world faces escalating species extinction, increasing urbanization, reduction of habitats, and widespread pollution, engaging in continuous thought and action toward planetary regeneration becomes imperative. This requires rethinking potential connections and fostering interconnections to enhance coexistence among all life forms. Thus, the ontological framework of BIO must evolve to embrace a more inclusive concept: the emergence of “others coming into being.”