The collective monograph Synthetic Becoming brings together research by artists, activists, and feminist technoscience practitioners concerned with sympoietic becoming with hormones and hormonally-active chemicals. The contributors examine effects of industrial, pharmaceutical, and more-than-human production and interplay of hormonally active molecules, asking: What does life re-assembled by hormones and hormone-mimicking chemicals look and feel like? Who are we becoming with them and how can we possibly be with them otherwise? Adopting a decolonial feminist, posthumanist, and new materialist approach, the book embraces queer ecological sensibilities and responds with a series of critical but hopeful provocations that embrace posthuman mutability and articulate our “synthetic becoming” in ways that facilitate caring relations and allow us to envision and enact hopeful futures with and despite these peculiar chemical agents.