Reposted from their website:
‘Muphry’s Law is the editorial application of the better-known Murphy’s Law. Muphry’s Law dictates that:
1. if you write anything criticising editing or proofreading, there will be a fault in what you have written; 2. if an author thanks you in a book for your editing or proofreading, there will be mistakes in the book; 3. the stronger the sentiment in (a) and (b), the greater the fault; and 4. any book devoted to editing or style will be internally inconsistent.
Muphry’s Law also dictates that, if a mistake is as plain as the nose on your face, everyone can see it but you. Your readers will always notice errors in a title, in headings, in the first paragraph of anything, and in the top lines of a new page. These are the very places where authors, editors and proofreaders are most likely to make mistakes.
It always pays to allow for Muphry in anything you write, or anything you are checking.’
Lest you never forget!