A lot of the answers that you will get to this question is going to depend on whether people interpret it as fictional monsters or the real-life ones. I'm going to try and cover all based, at least in terms of fictional monsters, so here are some books I suggest you read if they catch your fancy.

1. A Monster Calls by Patrick Ness - This one is rather obvious, but also not because it says "monster" right there in the title, but the monster in this book is not a traditional one. No, you see, this monster is a massive humanoid shaped yew tree that visits the protagonist in the middle of the night and tells him stories. Although this description doesn't make the monster sound very frightening, it does threaten to eat the protagonist if he doesn't tell him a true story of his own after listening to the ones by the monster. It is a really good book and has also recently been turned into a really good movie. While it is perhaps not the type of "monster" story you may be looking for, I would still recommend it wholeheartedly because it is awesome.

2. Jaws by Peter Benchley - I don't know about you, but I'm scared to death of sharks and I think this book had a lot to do with it. Like most other people I saw the movie first, of course, but when I returned much later to the book, I still found it very enjoyable. I think this is probably one of the rare cases where the movie actually enhances your reading experience as you can already picture the characters and setting more vividly. The other reason to read the book is that it isn't exactly the same as the movie. There are some added elements that make things a bit more interesting, but I'm not going to spoil anything here. And, of course, the shark is still pretty terrifying and definitely qualifies as a monster.

3. It by Stephen King - Almost any book by Stephen King would probably fit here, but It is one of his best "monster" books in my opinion. There is just something about clowns that are inherently creepy and the way that the one in this book just preys on the phobias and fears of kids is downright scary. Just a word of caution, the book contains a couple of things that both the two-part miniseries and the recent movie did not want to touch with a ten-foot stick, so don't read it if you are easily shocked.

4. The Strain by Guillermo Del Toro - Vampires count as monsters right, but instead of the same old Dracula story, why not read this interesting take on a classic monster by Guillermo Del Toro. Even if you don't know the name, you'll have definitely watched one of his movies like Blade 2, Hellboy, Pacific Rim, Crimson Peak or The Shape of Water. If you enjoy The Strain, also be sure to read the sequels, The Fall as well as The Night Eternal. There is a television series based on the books as well, but as with most of these things, it doesn't really capture the essence of the story.

5. Red Dragon by Thomas Harris - Not all monsters have fangs and claws with Red Dragon by Thomas Harris being a good example. It is the novel that introduced the world to Dr. Hannibal Lecter, who is a talented psychiatrist, who also happens to be a serial killer with a penchant for eating his victims. The book also received two sequels in the form of Silence of The Lambs, which was released in 1988, and Hannibal, which came out much later in 1999. Most people know these books from their movie counterparts, but they are great works that stand on their own as well.

The scariest monsters to me are always the human ones as we never expect our fellow man (or woman) to be as vicious and warped as some of them can be. If I had to pick one such "monster" from a book it would have to be Clayton Broom from the Lauren Beukes book, Broken Monsters. This guy is basically a failed artist who goes completely off the rails when his life doesn't turn out the way that he expected. When he becomes a serial killer he doesn't just murder his victims, but use his creative flair to transform them into something very disturbing. Like all good horror books, Broken Monsters does have some paranormal elements, but honestly the killer would be extremely chilling if he existed in real life.

There is certainly no shortage of monster fiction available and here are plenty of great recommendations already, so let me suggest something a little different for you. One only has to switch on the television to see that our country is completely obsessed with monsters, aliens, ghosts and other paranormal stuff. Some people are understandably very skeptical about these things, while others are passionate believers who are convinced that everything they see on these reality shows are the truth. Yet, even the most absurd and improbable "monster" myth or legend must have had its origins somewhere. This is a question that is explored in a non-fiction book called Medusa's Gaze and Vampire's Bite: The Science of Monsters by Matt Kaplan. The author is not only a science journalist, but also a fan of monster myths, which makes him an ideal candidate to explore the monster phenomena from an objective and scientific viewpoint. It is quite refreshing to read something about monsters that isn't written from a viewpoint of debunking everything or breathlessly believing even the most circumstantial of evidence. Matt doesn't just look at recent lore either, but explores stories from throughout history. If you enjoy monster stories, but need a break from all the fictional stuff, then you won't be disappointed by this book. I know that there are a couple of other ones that explore similar topics, but this one is the best that I've read so far.

For me the master of monster books will always be Stephen King. He has come up with so many memorable monsters over the years that it is hard to keep track of them all. In 'Salem's Lot he gave us vampires, while in Cujo, he manages to turn a rabid dog into a terrifying monster. Then there is Pet Sematary, that contains some very chilling zombies, and in his book The Tommyknockers, it is aliens that step into the role of monsters. Then there is one of my all time King favorites, Needful Things, where the monster is a man named Leland Gaunt, who may or may not be Satan himself!

As long as we are going with obscure books I'm going to recommend War with the News by Karel Čapek. He is the same author who wrote R.U.R and this book is written along similar lines, but still very good. The "monsters" in this book are basically a race of intelligent newts that are discovered by humans in the Pacific. As is usual for humans, they then enslaved these creatures and exploit them. This leads to growing tension that eventually erupts in a full blown war between the humans and the Newts. I've heard stories that the author actually used extinct giant salamander as the basis for his monsters. Fascinating to think that such things once walked the Earth (although obviously not as intelligent as the ones in the story I would presume.)

You want monsters? Here are a couple of them for you:

The Tescara from "It Lives in The Basement" by Sahara Foley. In terms of monsters, this one from the book It Lives in The Basement is pretty unique. I'm not going to describe it here, because most of the book involves people trying to figure out what it is and how to stop it, but let's just say you would not want to run into it.

Zombies from "The Hand That Feeds" by Michael W. Garza. Yes, I know that zombies are a dime a dozen these days, but they are still monsters and The Hand That Feeds is one of my favorite books featuring them. If you are looking for a lot of action, then this isn't the best book for you, but if you can appreciate a well told story with plenty of human drama, then go grab it now. It is about a couple who lose their son, only to see him come back from the dead as a zombie. What happens next I will leave up to you to find out.