A Blind Librarian Catalogued 40,000 Books by Smell — Scientists Confirmed She Was Right

For more than half a century, Maria Helena Soares navigated the labyrinthine stacks of Portugal's Biblioteca Nacional in Lisbon without ever seeing a single page. Born blind in 1931, she began working at the library as a clerk in 1953 and retired in 2005 at the age of 74. During that time, she developed an extraordinary personal cataloguing system based entirely on the smell of books.

Soares could distinguish between centuries of publication, types of paper, binding adhesives, and even the geographic origin of a volume — all through scent. Her handwritten index cards, numbering over 40,000, contained olfactory descriptions alongside standard bibliographic data: 'sweet lignin decay, Dutch linen rag, oak-gall ink, pre-1780' or 'acidic wood pulp, machine-cut, Leipzig binding glue, 1890s.'

Her colleagues regarded the system as a charming eccentricity. But in late 2025, a team of forensic chemists from the University of Coimbra, led by Professor Inês Calado, decided to put Soares's classifications to the test. Using volatile organic compound (VOC) analysis and gas chromatography, they examined 2,400 books that Soares had catalogued by smell and compared her assessments against scientific measurements.

The results, published this month in the journal Heritage Science, were staggering. Soares's dating estimates were accurate to within 15 years for 96.3% of the volumes tested. Her identification of paper origin matched chemical analysis in 91% of cases. Most remarkably, she had flagged 37 books as 'sick' — emitting what she described as 'a vinegar whisper beneath the must' — and every single one was found to be in the early stages of acidic deterioration that had gone undetected by visual inspection.

'She was essentially performing chemistry with her nose,' Professor Calado told reporters at a press conference in Lisbon. 'The VOC signatures she detected are the same ones our million-euro instruments measure. She simply learned to read them over decades of daily exposure.'

Soares, now 94 and living in a care home in Sintra, was reportedly delighted by the findings. 'I always told them the books were talking to me,' she said through her niece, who read her the study results. 'They just weren't listening.'

The University of Coimbra team is now developing an AI-assisted olfactory sensor inspired by Soares's system, designed to detect early-stage book degradation in libraries worldwide. They have named the prototype 'Helena' in her honor.

The discovery has also prompted the Biblioteca Nacional to digitize all 40,000 of Soares's index cards, creating what they call the world's first 'olfactory bibliography.' Several major research libraries, including the Bibliothèque nationale de France and the Library of Congress, have expressed interest in applying VOC analysis as a standard preservation tool.

'Maria Helena proved that knowledge doesn't require sight,' said the library's current director, António Brito Camacho. 'Sometimes it requires a different kind of attention entirely.'