The English idiom "don't judge a book by its cover" is a figurative phrase which means "you shouldn't judge significance of something by its outward appearance only".

It is easier and faster to look at the instantaneous outer features of an object or a person. Many cannot deal with the troubling feeling of doubt (fear) when conversing with a stranger so to make it less challenging for themselves, they put a label on their new associate and act accordingly.

For example, you see a good-looking person and a bad-looking person. You know nothing about them except their skin colour, their physical traits and fashion. Then what? You make all sorts of thoughts and make a massive data in a minute just taking a look of their outward appearance. You may get attracted to the good-looking one but that could be a disaster for your life. He/she may not possess any real ability or talent. He/she can even turn out to be corrupt too. Outward appearance can be greatly misleading. There are utterly valueless things that look so good and taking them on their face value is foolishness.

On the other hand, some of the ugly looking things possess immense value. Their appearance is in no way equivalent to the worth they have. A person must be judged on the basis of his/her capabilities and not on his/her external appearance. Many of the truly good and great person are respectful.

Therefore assessment of people on the basis of appearance is a futile approach.For some people book cover is the summary of whole book in one page. Designers use colours, pictures and text to give a good impression of the content that the reader will find inside. Book cover is a great tool to develop the curiosity of the reader as the world is really fast that we have only time to take a look on its cover, so the cover is where they either accept or reject the book. However the books with eye-catching covers do not really mean that it is worth reading, it could be a waste of your precious time.

So readers, do not get misguided by the outward appearance of anything whether a person, a book or a thing.