Intrinsically conducting polymers (ICPs) have attracted great attention because of their tunable properties and potential applications in multidisciplinary areas. Among the available ICPs, polyaniline (PANI) has found to be the most promising because of its ease of synthesis, low cost monomer, tunable properties, wide range of application possibilities and higher thermal stability compared to other ICPs. This book covers a detailed discussion on the different methods for the synthesis of PANI, different important properties of PANI and the experimental methods requires for the determination of those properties, mechanism of electrical conduction in PANI and the factors those influence the electrical conduction, problems of effective utilization of PANI and the methods adopted to overcome those problems and different applications of PANI due to its special properties with simple diagrams of device fabrication.