Deller's book will be his extensive life story; it is set to be published in Spring 2021. In addition it will be written alongside Edward Couzens-Lake; it will be published by Pitch Publishing.
More information will be released on it in due course as and when it is fully announced. He has revealed that he has began to write it.
https://twitter.com/KDeller138/status/1292818715780829190