The WHO Blue Books, formally known as the WHO Classification of Tumours, are an authoritative series of books classifying tumors by location and histopathology. They are compiled by expert consensus under the World Health Organization's International Agency for Research on Cancer (IARC) and are widely used by pathologists, cancer researchers, and specialists globally

. Key points about WHO Blue Books:

• The series began in 1956 and has evolved through several editions, with the latest being the fifth edition starting in 2019

• Each volume covers detailed information on tumor types, including cause, mechanism, diagnosis, epidemiology, and outcomes, with contributions from 150-200 experts

• The editorial board is led by Ian Cree and consists mostly of practicing pathologists who regularly update the classifications

• The books are published both in print and online, with the online version offering enhanced features like searchable content, whole slide images, hyperlinks, and personal note-taking

WHO Blue Books Online:

• The WHO Classification of Tumours Online is a subscription-based digital platform that provides access to the complete and updated content of the series

• It includes multiple volumes covering different tumor types, such as digestive system, breast, central nervous system, soft tissue, and more, with new volumes added regularly

• The online platform also features companion cytopathology reporting systems for tumor classification from a cytopathologist's perspective

• Subscribers benefit from advanced navigation, bookmarking, personal notes, and direct feedback options on the website

Access and Subscription:

• Access to the WHO Blue Books online is primarily through an individual or institutional subscription model; PDFs are generally not available for purchase or download legally

• Institutions often provide access to the print editions, but remote access to digital content typically requires a subscription

• The subscription is considered valuable for its comprehensive, up-to-date, and searchable content, which is crucial for pathology and oncology professionals

In summary, the WHO Blue Books are a definitive resource for tumor classification, available both in print and through a subscription-based online platform that enhances usability and access to the latest tumor classification standards worldwide