There will be spoilers in various books, movies, and TV shows. If you come across one that you haven't read or seen, please continue to the next paragraph.
Many book series just aren't made for one or the other. They are either really good at being movies, or they are really good at being TV shows. However, we rarely see both. When we do though, it can be really amazing to see all the different ways our characters can be produced. Here are two examples of book adaptations and how far they worked.
The Mortal Instruments: City of Bones by Cassandra Clare
The Mortal Instruments: City of Bones is our first example of a book-based adaptation that has dabbled in a little bit of both. In 2013, Cassandra Clare's urban fantasy came to life on the big screen starring Lily Collins. In New York City, a seemingly ordinary teenager, Clary Fray (Lily Collins), learns that she is descended from a line of Shadowhunters - warriors who protect humanity from evil forces. After her mother (Lena Headey) disappears, Clary joins forces with a group of Shadowhunters and enters Downworld, an alternate realm filled with demons, vampires, werewolves, and any other creature imaginable. Clary and her new friends, along with some old ones, must find and protect an ancient cup that holds the key to her mother's future. Unfortunately, though the book had an exceptional plot that the movie tried to uphold, the movie fell through... hard. Many critics and fans came back to say the that the bits and pieces the writers took out for times sake only made up for bigger plot holes and a less-than-seamless script.
So by the end of 2015, FreeForm, formerly known as ABC Family, decided they would take on the challenge. Though its show Shadowhunters didn't do as well as some would say and it definitely wasn't as good as I had hoped to begin with, it hasn't been awful. In Shadowhunters, Clary's mother is much more eager to share the family secret than normal as we see in both the book and the movie. There are some other very distinctive details that differ from the original book and movie, but I won't ruin the already damned. I do have to say though, you weren't rushed into the plot, you were introduced to the characters first, which is more than any of us could ask for. I'll admit I wasn't a fan of the casting, but many agree the series has much more potential now that it is on television.
The Adventures of Sherlock Holmes, The Case-book of Sherlock Holmes, and The Memoirs of Sherlock Holmes by Arthur Conan Doyle
Sherlock is another great example of a book series by Arthur Conan Doyle that has had multiple adaptations. For example, we have Sherlock Holmes, which is the movie version starring Robert Downey Jr (above).
Sherlock Holmes came to us in 2009. When a string of murders threatens London, it doesn't take long for detective Sherlock Holmes (Robert Downey Jr.) and his crime-solving partner, Dr. Watson (Jude Law), to find the killer, Lord Blackwood (Mark Strong). Blackwood has a bigger scheme in mind, however, and his execution plays right into his plans. The game is afoot when Blackwood seems to rise from the grave, throwing Holmes and Watson into a world of strange magic. With positive reviews, the movie was a hit or miss among fans. The movie itself was tremendous, though many die-hard Doyle fans agree the movie did not do Sherlock Holmes justice, and that the character and the character portrayal did not match up. If you weren't completely basing the movie on the books though, it was an enjoyable and exciting experience.
We have the American drama series Elementary starring Jonny Lee Miller.
Elementary is quite a different take on Sir Arthur Conan Doyle's classic character, as Sherlock Holmes flees London for present-day Manhattan after a stint in rehab. He arrives to find that his father has assigned a sober companion to live with him - Dr. Joan Watson, who is a former surgeon who gave up medicine after she lost a patient, and is now focused on helping addicts stay clean. However, Holmes has his own plan for keeping on the straight and narrow, throwing himself into his work as a police consultant in New York City. The two find that they make a good team and are soon cracking some of the most-difficult cases. Starting in 2012, the show has done exceptionally well with four seasons, a charismatic duo, however, CBS has yet to renew or cancel the series. Still, many don't agree with the way Sherlock Holmes is portrayed yet again. A reviewer in Rotten Tomatoes below states how fun Holmes and Watson were as compared to the characters in Elementary.
No one smiles in Elementary, least of all Lucy Liu as Watson. She looks like someone just ran over her cat. Jonny Lee Miller’s Holmes is marginally cheerier, but only when he’s being excessively nasty. -Rob Salem, top reviewer of Rotten Tomatoes
And then we have the British drama series Sherlock starring Benedict Cumberbatch.
In another more contemporary version of Doyle's work, Dr. John Watson is a war vet just arriving home from Afghanistan. He meets the brilliant but eccentric Sherlock Holmes when he advertises for a flatmate. Almost as soon as Watson moves into Baker Street, they are catapulted in mysteries, and Sherlock's nemesis, Moriarty, appears to have a hand in the crimes. This one, unlike its similar works, hit the jackpot for most viewers. All of Sherlocks' elements are present, along with the chemistry and relationship established between Holmes and Watson. It is modern but has high respect for its original story, and that is what many love about it.
Why didn't all the "screens" work? Although with the examples about, we do have the tv series and the movie franchise, but it was either one or the other. Unfortunately, you won't hear many fans say they loved both. So why couldn't the book be both a movie and a TV show? There could be a multitude of reasons, each one for different shows. In the matter of both TV and film, it could have been a poor script, poor casting, etc. But there are different reasons that a book can make a better show than a film, or vise versus. The most important aspect of good book-based TV, or any TV for that matter, is good characters. Yes, you can add all the little details you want, and yes, you can add as many twists and turns and loops that your heart desires, but if your characters stop developing, so does your show. No matter what happens, the characters need to grow with the plot. You can have some of the best plotlines in history, but if your character's best friend dies and nothing in him changes, fans are going to forget about your show as fast as your character forgot about his best friend.
Movies, however, are all about the story. An example I would like to introduce to explain my point is the recent movie, though not book-based, The Age of Adaline. This is one of my favorite movies ever, and if you have seen it, you know that it is one of the most unique stories you have ever heard. Think about the characters for a moment. There are very important things about the characters that literally make up the story. That's just it though, they make up the story. You don't watch Adaline adjust to the life she is given. You don't watch Flemming grow up, realizing with each passing day she is getting older than her mother. You just know they adjusted and you continue with the story at hand. If The Age of Adaline were a TV show, you would expect to see her life each passing day, and you would expect the show to revolve around the character adjusting. Not revolving around what happened because she adjusted.