Missing copyright permissions are the most common cause of delays to publication once a manuscript is complete. It is a legal requirement that authors and contributors obtain all necessary copyright permissions for third party materials including their own work. The link to Elgar copyright policy: Your guide to the essentials provides further information about copyright and clearing permissions.
Editors must also obtain documentation from contributors to show that they have cleared copyright permissions for third party materials in their chapters.
Please also bear in mind other serious legal considerations including libel and defamation, plagiarism (including self-plagiarism) and the importance of anonymising individuals and their data to comply with the General Data Protection Regulation legislation that applies to publications sold in Europe.
More information about these requirements can be found in the Elgar copyright policy page, and in the 'As you write your book or chapter' section of the author portal.
Please contact your commissioning editor if you have any questions.