Parliamentarians play a significant role in working with the Executive and others to promote International Humanitarian Law (IHL) and to ensure its effective implementation. This requires Parliamentarians and parliamentary staff to be well-informed. This handbook has been specifically designed by the Commonwealth Parliamentary Association (CPA) and the British Red Cross to help achieve this goal, taking into account the specific legal traditions and practices, and values, of Commonwealth countries. First published in 2019, this handbook was updated in March 2022.