I recently discovered how some book are so similar (also when it comes to author themes) that I decided to create a new series. I compared a familiar book with an unfamiliar one (you may still know them) and it doesn't matter if you've read only one of the two. These are some that look very similar to each other:
The Fault In Our Stars vs A Walk To Remember
Why? Both deal with heartbreaking diseases, strong female teenagers, love relationships and staying true to yourself. I love them both so much, but when I read and watch The Faulr In Our Stars I compared it so much with A Walk To Remember (I read and watched that a few years before). They're both really good as well
Pippi Longstocking vs Anne of Green Gables
Why? Both main characters are children and very witty and clever. I think they could have been best friends and the world totally would fit as well. They're also very easy to read and both well known and loved classics.
The Jungle Book(s) vs Burmese Days
Why? Both authors came originally from India (or their parents and moved to Great Britain) and these books are both about colonialisation and imperialism from the perspective of India so not from the western world. That's why I love them both, even though the setting is kind of different (Jungle Book has animals and jungle vibe). They both have other themes that are kind of similar as well. Only difference is, is that Jungle Book is from the perspective of a child and Burmese Days from a man in his twenties/thirties.
Did you discovered some books that are very similar to each other and if so: which ones?