"P.E.T Parent Effectiveness Training"
by Dr. Thomas Gordon helped me communicate better with my fiancé and family. It has brought me so much closer to them than I ever imagined. My mom and sister said I "grew up" but what they don't know is I simply learned how to communicate differently.
I recommend this book to anyone and everyone if you want your relationship (romantic, familial or platonic) to thrive.
(It says "Parent" but the methods work on everyone)