- "...the self-help book The Hairy Heart: A Guide to Wizards Who Won’t Commit has topped bestseller lists."
- — Albus Dumbledore[src]
The Hairy Heart: A Guide to Wizards Who Won't Commit was a Wizarding self-help book that topped bestseller lists. Presumably, it helped assist a witch or wizard to avoid having "a hairy heart," which was a Wizarding expression that described someone who was cold or unfeeling or who had trouble committing to a relationship.
The origin of the expression "to have a hairy heart" was the fable The Warlock's Hairy Heart, wherein the character, the Warlock, had hid his heart in his dungeon. This led him to having hardly any infatuation with any maiden and thus turning his heart hairy and his personality cold and untouched by any lady.
- The Tales of Beedle the Bard (Mentioned only)