Yes, you definitely judge a book by its cover. If you aren't sure, think about the last time you browsed a bookstore. You probably were looking at spines, assuming that you were in a store that didn't have the space to display all the front covers. The first thing your eye sees is color, then font (the design of lettering). Then you might pull from the shelf a spine that appeals to you, and check out the cover. At that moment, the cover design is communicating something to you.
Are you looking for a thriller? The cover might look something like this:

Immediately, you know this is a book that might keep you up at night, and it definitely will have you guessing until the last page. It's not a love story or a cozy mystery. This book will include creepy moments that make your palms sweat, probably some night scenes with rain, and certainly a few characters who make your skin crawl. This cover has a lot to say!
If you are in the mood for love, you will know you've found it when you see a cover like this:

This one will be light, with a touch of humor, and if you're a book lover, the plot is going to be exactly in your wheelhouse. The colors are happy, so we know that while there may be some angst within the storyline, we won't be pulling too many tissues from the box during this read. Their backs are turned to each other, so there might be a little mystery here. If you like contemporary romance, this cover will communicate that this is going to be a satisfying read.
Love dark fantasy romance? You would immediately be drawn to this cover if you were shopping for that very particular genre:

The cover is dark, which is a must for this genre. And we know that there will be an element of romance when we see the font (gold and curvy), and you can see the skeletons blended into the red background, which hints that we will be entering a world that isn't where we live now, exactly why readers of this genre keep coming back for more. Stepping into another world is great escapism. You know what you're getting with this cover (i.e., there won't be a cute meet in this story).
One more. This cover is classic memoir. Even if the genre wasn't made clear under the title, we can look at this one and immediately know one of the two people in the photos is going to tell us a story - in this case, it's both. We see a historical photo and an image of old letters in the background. This cover design fits the genre well.

That's our goal. Create a cover that clearly communicates the genre, tone, mood, and story inside. So the next time you're browsing in the local bookstore, or shopping online for books, remember that you are probably making some judgments on what you will read based on the cover.
Storia can help you create a cover that fits your genre, and will make you proud that your name is on it. We'll work with you to make certain your potential readers know what they are getting when they pick up your book. Cover design is included in our publishing package, or as a stand-alone service. Contact us to get started!