Follow KDKA-TV: Facebook | Twitter

WESTPORT, CT (CBS Local) – The family of a 96-year-old in Connecticut has found a hidden treasure trove dedicated to every book the grandmother ever read.

READ MORE: Pittsburgh Winter Weather: 1-4" Of Snow Expected To Fall Throughout Western Pennsylvania

Stefanie Dreyfuss, of Westport, passed away in mid-May, leaving behind several relatives and in-laws. Her daughter-in-law posted a photo on Twitter of the stunning find in the woman’s home. Each book review had been categorized using a completely original code created by Dreyfuss and filed away on hundreds of index cards over the years.

Lauren Tarshis’ post of the find quickly went viral, with over 18,000 fellow book lovers liking the post and over 2,500 people re-tweeting the image.

READ MORE: Student Loans And The Struggle Of Paying Them Off

“She kept track of all she read on index cards and recorded her opinion in code. This is the key to her code and the cards we found among her belongings,” Tarshis tweeted. Tarshis is the author of the New York Times Bestselling series “I Survived“, a fast-paced historical fiction from the perspective of a boy or girl who lived through a historical disaster.

The biggest takeaway from the 96-year-old’s coded collection is that she was a very tough grader. The numerous codes included:

  • RP: Readable Piffle
  • NFM: Not For Me
  • G: Good didn’t hold my attention
  • NMS: Not my style
  • RR: Readable
  • WOT: Waste of Time
MORE NEWS: Federal Appeals Court Orders Masking Policy To Be Enforced In Upper St. Clair School District

The opinionated reader’s daughter-in-law shared another photo a few days later after discovering a second hidden collection. Dreyfuss (who immigrated to the U.S. in 1947) had also saved her favorite quotes over her many decades in America.