Our primer is an elementary introduction to the complexities of use of transcriptomics in medical care. Focusing on chronic inflammatory response syndrome (CIRS), this short book leads us through the jargon of gene names, gene symbols and the maze of transcription factors to help us begin to understand how differential activation of genes underlies all chronic illness. In the specific case of CIRS, pertinent metabolic pathways are presented, populated with genes vital to the diverse processes involved in systemic inflammation. The goal is to show the reader the way to expand insights beyond the idea of mere presence of a gene to an understanding of interplay of environmental exposures and gene activity. Now that we have therapies that target the genes of specific pathways, we hope to bring use of transcriptomics to the tool box of healthcare providers