# Error: ! LaTeX Error: File `book.cls' not found [closed]

I am using Ubuntu on my laptop.

I am new to using LaTeX. I have recently installed Texmaker and I am writing a dissertation; I downloaded a template somewhere from the internet. It has been working fine. But today, when I tried to compile it into a PDF, I got this error:

``````! LaTeX Error: File `book.cls' not found.
``````

I have looked at other posts, but I have no idea what they meant. Can someone explain to me in layman terms, how can I solve this problem ?

Texmaker said the error is produced in `Latex/Classes/PhDthesisPSnPDF.cls` line. So I opened the file and this is what I have from line 31 to line 37

``````%If you want to use a Book style document then uncomment the following 3 lines and comment the above 8 report style lines:
\DeclareOption*{\PassOptionsToClass{\CurrentOption}{book}}
\ProcessOptions\relax
\ifx\pdfoutput\undefined
Does the file `book.cls` exist in your TeX distribution? It should be at `TEXMF/tex/latex/base/book.cls`. – ChrisS Aug 28 '13 at 8:41
I just tried `cd TEXMF/tex/latex/base/book.cls`, the directory TEXMF doesnt seem to exist. How do I find my Tex distribution in ubuntu ? – user1769197 Aug 28 '13 at 8:50
`TEXMF` is an acronym for the root directory of your TeX distribution. Where exactly the root directory is located varies across TeX distributions. Please post a minimum working example (MWE) that generates the error messages you're encountering. All one can tell is that it looks like you're using the document class contained in `./Latex/Classes/PhDthesisPSnPDF.cls`, but it's not clear who this class file then tries to invoke the `book` document class. – Mico Aug 28 '13 at 8:54