This book aims to create a variety of learning activities in Microteaching classes to prepare pre-service English teachers (PSETs) to face the demands of 21st century learning that prioritizes 4C Skills (critical thinking and problem solving, creativity, collaboration, and communication) in addition to teaching techniques. The book is in line with the demand of the Indonesia Ministry of Culture and Education to prepare teacher training and educational institutions in enhancing pre-service teachers' critical thinking and problem-solving as the most important skills in the 21st century.