Directory of Social Change are well known for their publications, and they have just published an updated version of The Fundraising Handbook.
The Complete Fundraising Handbook has been helping fundraisers make the world better since it was first published in 1992. Comprehensively revised by new author Robin Peake, the eighth edition of this title has more than earned its place on your bookshelf. It is the most complete reference guide to fundraising, with detailed information about the theory and practice of effective fundraising.
It does include a small section on data protection, which I was pleased to contribute to.
You can find out more and order paper or digital copies with the link https://www.dsc.org.uk/publication/the-complete-fundraising-handbook/.