This paper reviews the fourth generation universal bonding system and highlights its supremacy over the earlier bonding systems. This new system has the ability to bond to all dentally related surfaces and its hydrophillic nature allows the advantage of bonding in a naturally moist environment. The effect of acid on dentine and the role of hydrophillic primers in the formation of a collagen-resin complex are described in relation to obtaining good bonding and adhesion. A new fourth generation universal bonding system. ALL-BOND 2, is discussed in the light of these developments and its features compared to those of the ideal bonding system.