Asphaltenes are molecular substances that are found in crude oil, along with resins, aromatic hydrocarbons, and alkanes (i.e., saturated hydrocarbons). Asphaltenes in the form of distillation products from oil refineries are used as "tar-mats" on roads. This new book discusses the characterisation of alphaltenes and crude oils using near-UV/visible absorption spectroscopy. An overview of alphaltenes in petroleum and the cause of sediment deposition during production and refining is examined as well as the effects of magnetic fields on the paramagnetic, antioxidant, and viscous properties of oils and resin-alphaltene components. Insights into the structural characteristics of asphaltenes and its geochemical significance is also discussed.