Sustainability in print refers to the practice of publishing and producing books in an environmentally-friendly manner. This can include using recycled or responsibly-sourced materials for the production of the book, implementing energy-efficient printing processes, and promoting digital reading options. Penguin is a publisher that has been taking steps to incorporate sustainability into their book production, such as using Forest Stewardship Council (FSC) certified paper and implementing digital printing technology. Additionally, they have a range of environmental books that raise awareness and educate readers on issues related to sustainability and the environment.