The discovery of high temperature superconductors HTS with critical temperatures Tc above the liquid Nitrogen boiling temperature 77K, stimulated the scientific community. Four families of HTS were discovered. These are Yttrium, Bismuth, Thallium, and Mercury based superconductors. Despite the extensive research carried out after that, practical applications faced limitations. One of the limitations is the fact that the maximum Tc is still far below room temperature. Various chemical-processing methods can be used in hope to overcome the first problem. In this book, doping with Boron and Lithium to improve the properties of Thallium based HTS have been studied. Another limitation is the fact that the maximum current carried by a HTS, namely critical current Ic, is actually not infinite. In this regard, texturing of superconducting grains and irradiation are very successful methods to improve the limiting Ic. In this work, the production of superconducting tapes and the effect of magnetic field and gamma irradiation on them have been studied. This book is mostly useful for higher-grade undergraduate students, graduate students, materials scientists, and experimental physicists.