We don't like to say "no", do we! It feels like we are letting someone down. And yet common sense dictates that sometimes we must.
It is easy to dwell on what we may consider our moral or social responsibilities - loving our neighbours, putting others first, caring for the less-well-off. These are fine principles, which we can readily apply most of the time. However in life we are sometimes in conflict, between our wishes and needs, and what others may demand of us. In the worst case others may appeal to our moral principles to manipulate us to concede to their wishes. This is emotional blackmail. There are plenty of examples in this forum, of carees, of relatives, of officials from social services, hospitals, the welfare state and others, making demands that we cannot meet.
This book helps you to handle these conflict situations. How to assert your point, calmly, politely, non-aggressively and with dignity.
The book is "When I Say 'No', I Feel Guilty", by Dr Manuel J Smith. Published by Bantam, ISBN 0-553-26390-0. It was first published in the 1970s but still seems to be readily available. Try your local bookshop, library or on line.
The first three chapters are, I admit, rather heavy reading. They set out sociological principles of how people inter-react, and our basic rights. But persevere, they set the scene for the rest of the book. It really gets going in chapter 4. The author gradually introduces, with practical scenarios, coping techniques such as broken record, fogging, negative assertion and others. He also describes "workable compromise"; sometimes it is just impossible for us to be granted everything we ask for, and there are ways to negotiate a sensible compromise.
Slightly dated in style but with plenty of good advice nevertheless. Well recommended as a good read, and also something to dip into subsequently for reference.