This 1988 ESCAP manual provides a comprehensive framework for training junior statisticians in national statistical systems, particularly in developing countries of the Asia-Pacific region. It was revised following the 1987 ESCAP/SIAP Expert Group Meeting in Bangkok to address growing needs for statistical capacity and human resource development. The manual is organized into five courses covering basic statistical concepts, methods, data collection design, data processing and presentation, and statistical systems and standards. It emphasizes practical training through exercises, fieldwork, and projects while highlighting the role of statistics in government planning, policy-making, and development. Overall, it serves as a foundational guide to improve the quality, coordination, and comparability of official statistics at national and international levels.