This is another of the fantastic new books published in the Duke Hawkins Books series. This volume is number 11 of the series and focuses on the Harrier II/AV-8B as operated by the RAF, the United States Marine Corps, the Spanish Navy, and the Italian Navy. The volume includes at least one photograph of a jet from each country. Apparently, the authors considered just doing a book on the RAF versions, but in the end decided to do an expanded book covering all versions of the Harrier II.
The AV-8B/Harrier II has its origins in a USMC requirement for a replacement for the AV-8A Harrier. McDonnell Douglas designed and proposed a much upgraded and improved Harrier, resulting in the AV-8B Harrier II. Different variants were developed to meet the requirements of the RAF and the USMC resulting in the Harrier GR.7, GR.7A, GR.9 (and associated trainers T.10 and the T.12), AV-8B, AV-8B Night Attack, and the Harrier II Plus (and the TAV-8B) for the USMC.