Conducting polymers have many applications in device fabrication. Organic semi-conductors are different from inorganic ones. In conducting polymers the conducting properties are due to the presence of conjugated pi-electron backbone in these polymers. Due to this, these polymers display low energy optical transitions, low ionizing potentials and high electron affinities. Tailoring of their properties is very important for effective applications. This book explains the use of SHI irradiation technique to modify the properties of conducting polymer films.