Polymeric adhesion bonding problems are pervasive throughout the plastics industry. Plastic substrates are difficult to bond because they are hydrophobic (not naturally wettable) materials; possess poor surface wettability (i.e., low surface energies); non-polar, inert structures; and poor surface chemical functionality. Two & three-dimensional products often include bonding plastic-to-plastic, plastic-to-metal, plastic-to-composite, optomechanical and more. Adhesion bonding applications are not limited only to adhesives (epoxies, urethanes, acrylics, silicones, etc.), but include adhesion of printing inks, paints and coatings, encapsulants, potting compounds, metallization and more. This article discusses the basic science of "Contact Angles, Surface Wetting and Chemical Activation" to achieving strong adhesion bond strength. Surface wetting testing involves measuring the contact angle. For many applications it may only be necessary to examine the static equilibrium contact angle using dyne solutions in accordance to a documented test procedure such as ASTM D2578.