A review of current clinical research has demonstrated that successful attachment with resin-based bonding systems is achieved through brief acidic conditioning of dentin, followed by thorough coverage with resin priming and bonding agents. This article discusses factors of clinical relevance in achieving optimal results. Effective priming, using multiple coats to enhance resin penetration to the full depth of dentinal demineralization, is crucial. A thin, uniform layer of bonding resin is a critical, elastic intermediary for absorbing stresses of polymerization shrinkage. An air stream should be used only for evaporation of solvent and not for spreading bonding resin, because use of an air stream causes uneven thinning of this valuable intermediate layer. Contamination of the dentinal surface with excessive moisture or solvent or the presence of air voids will make bonding unpredictable under clinical conditions. Adequate etching of peripheral enamel continues to be an important factor in the long-term retention of adhesive restorations.