This book presents the basic results on studies of the interaction of anti-cancer Actinomycin antibiotics with DNA. It focuses on interactions of heterocyclic anti-tumor antibiotics (Actinomycins, as typical example) with DNA, poly-nucleotides, oligonucleotides, and aggregates of purines, using spectroscopic methods. Experimental data, various models of structures of the complexes and their physical and chemical properties are described, and possible approaches for delivery of heterocyclic antibiotics to DNA are also discussed.