I managed to find a copy on Amazon. https://www.amazon.com/gp/product/0316339105/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
Another by yukito ayatusji is a mystery horror light novel. its completed at 1 volume. there is a sequel called another s/o but thats basically just a side story after the first novel so you dont need to read that if you dont want to since the first novel finishes itself. https://www.amazon.com/Another-light-novel-Yukito-Ayatsuji/dp/0316339105/
heres the blurb.
In the spring of 1998, Koichi Sakakibara transfers to Yomiyama
North Middle School. In class, he develops a sense of unease as he
notices that the people around him act like they're walking on
eggshells, and students and teachers alike seem frightened. As a chain
of horrific deaths begin to unfold around him, he comes to discover that
he has been placed in the cursed Class 3 in which the student body head
count is always one more than expected. Class 3 is haunted by a
vengeful spirit responsible for gruesome deaths in an effort to satisfy
its spite. To stop the vicious cycle gripping his new school, Koichi
decides to get to the bottom of the curse, but is he prepared for the
horror that lies ahead...?
I haven't seen the anime so I can't really comment on how much it covered, but much of the differences between the anime, manga, and novel can be found on the Another Wiki. I also thought that you might like to know that both the anime and manga are based off of a novel (not light novel series, a single 700 page novel) by Yukito Ayatsuji that can be bought here.
Wait really? I bought this (https://www.amazon.com/dp/0316339105/ref=olp_product_details?_encoding=UTF8&me=) and seeing this (https://www.amazon.com/Another-Vol-2-light-novel-ebook/dp/B00AA18Z9C/ref=sr_1_10?s=books&ie=UTF8&qid=1494903607&sr=1-10&keywords=another+light+novel) makes me think that there's a volume 2 somewhere. (sorry if those URLs are messed up)
I meant the light novel of another https://www.amazon.com/Another-light-novel-Yukito-Ayatsuji/dp/0316339105 I cant seem to find a 2nd hardcover book of it