Willoughby has contributed writings to the following books:

Radical Mycology: A Treatise on Seeing and Working with Fungi (Peter McCoy, 2016), Available now from Chthaeus Press

Mushroom Essences: Vibrational Healing from the Kingdom Fungi (Robert Rogers, RH, AHG, 2016)   To be released July 2016 by North Atlantic Press

Notes from the Leading Edge: A Supportive Field Journal for Learning and Documenting Fungal Taxonomy (Mara Penfil, 2015) Available from Female and Fungi