The present study represents both a case study about microbial degradation by microorganisms that can cause damage to old man-uscripts as well as health threats to the librarians. Most of the microbiological damage started in poor environmental conditions of storage and display. The study aims to characterize the microbes that cause microbial deterioration of the historical books. Microbial swabs were taken from the manuscript under study, and the isolated orga-nisms were identified using the sequencing of rRNA of the ITS region of the rDNA gene at Solgent company, South Korea. The results showed three bacterial species: Micrococcus luteus (MH450098), Microbacterium schleiferi (NR044936T) and Bacillus subtilis (NR1126 29T), as well as: two fungal species Aspergillus ustus (NR134245T) and Aspergillus chevalieri (NR135340T). The genus Aspergillus ustus was the dominant genus isolates. It was followed by Aspergillus chevalieri. The biological activities of the isolated microorganisms were studied and showed the highest activities cellulolytic and proteolytic activities observed by Aspergillus chevalieri. Modern devices were used to study the infected and the uninfected parts of the same manuscript by taking some of the falling pieces from the manuscript, such as (light microscopes, SEM with EDXS, and FTIR). Surface observation obtained by light microscopy showed microbial infiltration on infected paper, significant changes detected by SEM in some elements decreased the percentage, and the other element percentage increased. Moreover the other elements dis-appeared. The chemical changes inside the paper structure resulted from the degradation of large organic compounds (chemical functional groups) by the action of extra-cellular enzymes secreted by deteriorating fungal species, converting these compounds into smaller ones using the FTIR.