"Overall, Learn R: As a Language, Second Edition, is an excellent book that offers a comprehensive introduction to R programming. It is well-suited as a textbook for an introductory R course, provided it is paired with appropriate instructional support. The book also serves as a reliable reference due to its meticulous and thorough treatment of technical details. Another standout feature is the inclusion of advanced references at the end of each chapter, guiding readers toward further exploration. This book is particularly suitable for individuals who already have some exposure to R programming and aspire to advance their skills. By providing a solid and concrete understanding of R fundamentals, it lays the groundwork essential for mastering more advanced techniques and becoming a proficient R programmer."~Haihan Yu, The American Statistician