are there offical work books for IMO

Yes, there are official workbooks available for the International Mathematical Olympiad (IMO). These workbooks are published by the IMO and contain a collection of problems and solutions from previous IMO competitions. They are designed to help students prepare for the competition by providing them with a range of challenging mathematical problems to solve. Additionally, there are many unofficial workbooks and study guides available from various publishers and websites that can also be helpful for students preparing for the IMO