(Image credit: Apartment Therapy )
Field Guide to Stains • $12 • Amazon

My father is a reference librarian so I shouldn't have been surprised that he sent my sisters and I a copy of this book a few years ago. Sure, you can look stuff up online, but quickly pulling this little volume off the shelf for guidance (for practically any stain you can imagine) has saved the day in my home many times. A practical, useful addition to your family's home reference section.