 Phage therapy has been used for over a century to treat bacterial infections, but its use was largely replaced by antibiotics. However, with the rise of antibiotic-resistant strains of bacteria, phage therapy is once again being considered as a viable option. Recent advances in phage genome engineering techniques such as CRISPR-Cas9 have enabled researchers to create customized phages with enhanced lytic activity against certain bacterial species. This review summarizes the current state of phage therapy and provides insight into how phage engineering can be used to develop new phage-based therapeutics. This article was authored by Kushal Kembadi, Gargi Bhattacharji, Nisargo Hill, and others.