The central theory involves an understanding of the distinction between errors of ignorance, and errors of ineptitude. Essentially making a mistake because you did not know better, and making a mistake because you executing what you do know incorrectly.
From there, countless examples and anecdotes litter the text making a crystal clear, iron clad argument that is difficult to ignore and inspires immediate action.
The more complex the task the more essential the need for a checklist. Furthermore, no undertaking is immune from the benefits of a checklist.
Any professional would be doing themselves a disservice by not reading The Checklist Manifesto!