Designed primarily for undergraduate students in microbiology, this book offers a clear and structured introduction to the fundamental principles of molecular biology and genetic engineering. From the expression and regulation of genetic information to the main techniques used to study and manipulate nucleic acids, it explains the essential mechanisms involving DNA, RNA, transcription and translation. Particular attention is given to laboratory methods such as gel electrophoresis, molecular hybridization, DNA sequencing, PCR, RT-PCR and quantitative PCR. The second part introduces the foundations of genetic engineering, including restriction enzymes, DNA ligases, plasmids, cloning vectors, bacterial transformation, genomic libraries and recombinant protein production. Richly illustrated with diagrams and practical examples, this academic resource provides students with the scientific foundations needed to understand modern microbiology, genetics and biotechnology, while offering a useful reference for anyone wishing to strengthen their knowledge of molecular techniques.