Dive into the first of five lectures on amplitudes and their applications, delivered by Yu-tin Huang from National Taiwan University as part of the III Joint ICTP-SAIFR/ICTP-Trieste Summer School on Particle Physics. Explore cutting-edge concepts in particle physics over the course of this 1 hour and 28 minute session, gaining insights into the fundamental principles and practical applications of amplitude calculations. Engage with advanced topics presented by a leading expert in the field, setting the foundation for a comprehensive understanding of this crucial area in modern physics research.