This edition has changes that relate to egress paths, so they have used that theme on the cover design.
This describes the means of operations, quantity required, and recommended inspection procedures and scheduling.
This talks about door props, latches, crash bars, automatic closers, painting doors, and identifying Fire Doors.
Many of the NFPA publications have companion Handbooks that are available that break-down the codes and standards into manageable concepts with great graphics and explanations describing both proper and improper conditions.
Put these books in your budget. Each one usually has a 3 to 5 year update cycle, so setting aside the funding for each of these should be a simple task. If you need justification for the expenditures, then ask the powers that be how you are supposed to do your job without the actual books that define the Laws you must obey and the Standards to which you should adhere.
Warning: Reading these books may induce drowsiness. Do not drive or operate heavy machinery while reading them.