I had been very unselective about the books I read so I let my elders select them for me. My dad bought many books for me that I used to read. My Grandfather gifted me a Qur'an-e-Majeed alongwith a book on Hudood-o-Taazeerat (Punishment) and a couple of Hakeem Saa'di (The greatest scholar of Persia (Iran)) namely Hikayat-e-Gulistan-e-Saadi and Hikayat-e-Boostan-e-Saadi which were all awesome books MashaALLAH. My dad used to gift me a lot of books related to history and Islamic in general. So, I used to read an awesome collection of books AlhamduLILLAH.
But now I'm completely changed about choosing books. I'm very very selective. I don't pay attention to a lot of books now. Only a few... very few. Because of the fact that mostly books are filled with propaganda and people's own thoughts. Which I'm mostly not interested in. Because I've seen it many times that thoughts of the people don't conform with Islam. So, if a thinking is not according to Islam, it's wrong. You might think I'm a fundamentalist or something, but that's the way I am. So, following are the books I found the best among them.
1. The Qur'an (The King of All books)
2. Sahih Bukhari ( The second in truth )
3. Tafseer - Ibn -e- Kaseer (Kathir) (I only like this Tafseer because Ibn-e-Kathir (RA) didn't write anything from himself. It's a collection of Ayah and Ahadith related to those Ayah (Verses from The Qur'an))
4. Kashf-al-Mahjoob ( Author: Hazrat Ali Hajveri (RA), Translation: Maulvi Feroz-ud-Din) (If the translation is someone else's I wont accept it so consider it fixed.)
5. Hudood-o-Tazeerat (written by an ex-chief justice of Pakistan) (This book has nothing to do with the current rules and regulations of Pakistan and is just about the rules and regulations of Islam That's why I like it.)
6. I love to read the Story of Hazrat Mohammad (Peace be upon him), but I have found none so worthy. so I read "Pyaray Nabi ke Pyari Kahanian (URDU)" and "Seerat-un-Nabi (Peace be upon him) by ... (I can't remember his name but he's a worthy author hope to remember him soon InshaALLAH)"
Please, whenever you decide to read a book on Islam, Please please please check for it's authenticity. The above discussed books are the most authentic in their fields and will represent the true face of Islam. The books written now can be a part of propaganda going on in favor of or against Islam. Reading books is a great hobby, but you should know what you're reading. I may be an extremist in selection of books, but this is my mindset. I may be wrong in my mindset, but I don't feel it. People may have worked really hard when writing a book on Islam, but sometimes, there are errors we can not understand. So, please be aware when selecting and reading an Islamic book.
ALLAH show us the right path and keep us firm on it! A'meen!