This book is a ready and updated version along with references of Carpometacarpal Osteoarthritis of the base of the Thumb. It also lists the original research work, which first appeared as The Results of Excision of the Trapezium- Iyer, K.M. (1981) The Hand 13:246-250 and also referred to in Wheeless' Textbook of Orthopaedics- wheelessonline.com- Osteoarthritis- CMC Arthritis- Excision of the Trapezium. It also lists the evolution of treatment and its alternate ways for managing this condition. I have been following it up with 30 references and 21 citations till today (10/7/2017). Full details may be seen on my website kmohaniyer.com. I have been inspired by my respected teacher late Geoffrey V Osborne as it has been dedicated to him and my family.