The article discusses the challenges in describing microbial diversity due to the failure of microbiologists to cultivate many microorganisms. Traditional methods like the plate count anomaly fail to capture the true diversity, as many microorganisms are not culturable. To address this, the analysis of rRNA molecules has emerged as a promising solution. This approach allows for the identification of microbial populations without cultivation by analyzing rRNA sequences. The process involves extracting rRNA, sequencing, and designing probes for comparative analysis. Techniques like quantitative dot blot hybridization and whole-cell hybridization enable the detection of specific microbial cells in their natural environments. The use of nested probes enhances the accuracy of identification. The rRNA approach has been applied to various microbial symbioses, including those in invertebrates, insects, and protozoa. It has also been used to identify pathogens and study microbial communities in environments like the ocean and soil. Despite its potential, challenges remain, such as sequence retrieval biases and the need for improved sensitivity in hybridization techniques. The rRNA approach offers a cultivation-independent method for microbial identification, although it cannot replace traditional cultivation methods entirely. The study highlights the importance of molecular techniques in understanding microbial diversity and their applications in various ecological and medical contexts.The article discusses the challenges in describing microbial diversity due to the failure of microbiologists to cultivate many microorganisms. Traditional methods like the plate count anomaly fail to capture the true diversity, as many microorganisms are not culturable. To address this, the analysis of rRNA molecules has emerged as a promising solution. This approach allows for the identification of microbial populations without cultivation by analyzing rRNA sequences. The process involves extracting rRNA, sequencing, and designing probes for comparative analysis. Techniques like quantitative dot blot hybridization and whole-cell hybridization enable the detection of specific microbial cells in their natural environments. The use of nested probes enhances the accuracy of identification. The rRNA approach has been applied to various microbial symbioses, including those in invertebrates, insects, and protozoa. It has also been used to identify pathogens and study microbial communities in environments like the ocean and soil. Despite its potential, challenges remain, such as sequence retrieval biases and the need for improved sensitivity in hybridization techniques. The rRNA approach offers a cultivation-independent method for microbial identification, although it cannot replace traditional cultivation methods entirely. The study highlights the importance of molecular techniques in understanding microbial diversity and their applications in various ecological and medical contexts.