Antimicrobial peptides (AMPs) have been studied for three decades, yet their molecular mechanism of action remains unclear. This review summarizes current knowledge from synthetic vesicle experiments and microbial experiments, focusing on their differences. Microbial experiments use much higher peptide:lipid ratios than vesicle-based experiments. To bridge this gap, the "interfacial activity model" is proposed, based on an experimentally testable molecular image of AMP-membrane interactions. This model may aid in designing novel AMPs. AMPs are cationic, amphipathic peptides with broad-spectrum microbicidal activity, primarily through membrane permeabilization. Unlike nonspecific lytic toxins, AMPs have minimal cytotoxic effects on host cells. AMPs are found in all organisms, including humans, and have been engineered de novo or from natural sequences. Much of the literature focuses on biophysical characterization and structure-function studies in model systems like lipid vesicles or detergents. Despite extensive data, compelling structure-function relationships in AMP research are rare. Activity depends more on amino acid composition and physical-chemical properties than specific sequences or structures. This phenomenon is termed "interfacial activity," referring to a molecule's ability to bind to membranes, partition into the membrane-water interface, and alter lipid packing. Interfacial activity depends on the balance of hydrophobic and electrostatic interactions between peptides, water, and lipids. AMPs interact with microbial membranes, which are typically anionic and rich in lipids like phosphatidylglycerol or cardiolipin. AMPs can permeabilize these membranes, leading to membrane disruption, leakage, and cell death. However, not all AMPs permeabilize membranes; some may have alternative modes of action, such as translocation across membranes without extensive permeabilization. AMPs can also affect intracellular components, including DNA and chaperonins. Model membrane studies show that AMPs interact with and perturb lipid bilayers. However, the variable nature of AMP activity and experimental conditions complicate interpretation. AMPs can cause membrane aggregation, fusion, phase separation, and lipid translocation. Some effects may not relate to antimicrobial activity and could be experimental artifacts. The prevailing transmembrane pore models suggest AMPs form pores or channels through membranes. However, evidence for specific pores in vesicles is limited. The "carpet model" and "detergent model" are common phenomenological models, but they lack molecular or physical-chemical basis for membrane permeabilization. Recent models, such as those based on molecular shape or lipid phase separation, provide a physical-chemical foundation for AMP activity. AMPs may not form transmembrane pores. Studies show that AMPs can cause slow leakage of vesicle contents, suggesting membrane disruption rather than pore formation. The "two-state transition" model explains this as external binding followed by critical destabilization of the bilayer. AMPs may also translocate acrossAntimicrobial peptides (AMPs) have been studied for three decades, yet their molecular mechanism of action remains unclear. This review summarizes current knowledge from synthetic vesicle experiments and microbial experiments, focusing on their differences. Microbial experiments use much higher peptide:lipid ratios than vesicle-based experiments. To bridge this gap, the "interfacial activity model" is proposed, based on an experimentally testable molecular image of AMP-membrane interactions. This model may aid in designing novel AMPs. AMPs are cationic, amphipathic peptides with broad-spectrum microbicidal activity, primarily through membrane permeabilization. Unlike nonspecific lytic toxins, AMPs have minimal cytotoxic effects on host cells. AMPs are found in all organisms, including humans, and have been engineered de novo or from natural sequences. Much of the literature focuses on biophysical characterization and structure-function studies in model systems like lipid vesicles or detergents. Despite extensive data, compelling structure-function relationships in AMP research are rare. Activity depends more on amino acid composition and physical-chemical properties than specific sequences or structures. This phenomenon is termed "interfacial activity," referring to a molecule's ability to bind to membranes, partition into the membrane-water interface, and alter lipid packing. Interfacial activity depends on the balance of hydrophobic and electrostatic interactions between peptides, water, and lipids. AMPs interact with microbial membranes, which are typically anionic and rich in lipids like phosphatidylglycerol or cardiolipin. AMPs can permeabilize these membranes, leading to membrane disruption, leakage, and cell death. However, not all AMPs permeabilize membranes; some may have alternative modes of action, such as translocation across membranes without extensive permeabilization. AMPs can also affect intracellular components, including DNA and chaperonins. Model membrane studies show that AMPs interact with and perturb lipid bilayers. However, the variable nature of AMP activity and experimental conditions complicate interpretation. AMPs can cause membrane aggregation, fusion, phase separation, and lipid translocation. Some effects may not relate to antimicrobial activity and could be experimental artifacts. The prevailing transmembrane pore models suggest AMPs form pores or channels through membranes. However, evidence for specific pores in vesicles is limited. The "carpet model" and "detergent model" are common phenomenological models, but they lack molecular or physical-chemical basis for membrane permeabilization. Recent models, such as those based on molecular shape or lipid phase separation, provide a physical-chemical foundation for AMP activity. AMPs may not form transmembrane pores. Studies show that AMPs can cause slow leakage of vesicle contents, suggesting membrane disruption rather than pore formation. The "two-state transition" model explains this as external binding followed by critical destabilization of the bilayer. AMPs may also translocate across