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.

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.

READ MORE: Ketanji Brown Jackson Joins US Supreme Court

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. “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.

READ MORE: Both Sides In Abortion Fight Wait To See How Far DeSantis Will Go In Florida

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: Woman Accused Of Killing Elite Cyclist Is Captured In Costa Rica After 43 Day On The Run

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.