Initial research on microorganisms was predicated on the idea that a single cell would be similar to the entire population of microbes. However, due to the developments in single-cell technology, it is now known that the microbial population is not homogeneous. The isolation of a single cell for research purposes can often be challenging, as it may disrupt the cell’s cellular composition. With the advent of transcriptomics, isolating individual cells is no longer necessary. The ability to evaluate the expression of a limited number of genes at the single-cell level has been made possible by genomic transcriptomic approaches. The interpretation of microbes and the elucidation of metabolic maps of microorganisms have been made possible through transcriptomic investigations. The application of transcriptomics in microbial studies has facilitated the identification of microorganisms responsible for nutrient recycling in the environment, as well as the understanding of the mechanisms underlying various diseases. This chapter covers the fundamentals of bacterial transcriptomics and the methods employed in this field.