This book emphasizes the important role of invertebrates in forensic sciences in the detection of crimes, determining the time and place of death, estimating the minimum Post-Mortem Interval (PMI), and determining the cause of death. The initial chapter discusses the forensically essential invertebrates, especially flies under Order Diptera. Further, the book highlights the importance, biology, taxonomy, and biodiversity of flies under Order Diptera with forensic importance. It also discusses the Cuticular HydroCarbons (CHC) and spectrometry-based studies reported from flies and larvae of forensic importance. It further reviews the importance of DNA barcoding in molecular taxonomy-based studies on forensic flies through understanding, identification, and grouping the organisms. Towards the end, this book presents the applications and limitations of forensic entomology in cases of animal cruelty to a veterinary professional.