Dr. Michael Buonocore introduced the profession to the concept of adhesive restorative dentistry over 50 years ago, and dentistry has never been the same. Since that time numerous formulations have been offered and etch-and-rinse and self-etch adhesives have been introduced. As with many products, strengths and shortcomings of various adhesives are only appreciated after their introduction and use in clinical practice. The sixth edition of this Guide provides an updated review of the essential information related to adhesives as the basis for discussing their clinical applications. The critical comparison of adhesives allows the practitioner to select the system most applicable to the clinical situation. The subject of dental adhesives is still a work in progress and the practitioner is urged to follow the evidence-based literature as it becomes available.