Adhesive bonding is a widely used industrial joining process in which a polymeric material is used to join two separate pieces (the adherends or substrates). This chapter begins with a discussion on the advantages and disadvantages of adhesive bonding, followed by a section providing information on the theory of adhesion. The chapter then describes the considerations for designing adhesively bonded joints and for testing or characterizing adhesive materials. The following section covers the characteristics of the most important synthetic adhesive systems and five groups of adhesives, namely structural, hot melt, pressure sensitive, water based, and ultraviolet and electron beam cured. The chapter ends with a discussion on some general guidelines for adhesive bonding and the basic steps in the adhesive bonding process.