Books can be found and bought in a library, book shops (Waterstone's, WhSmith, etc.) Books can also be found in school libraries and also online you have access to some amount of e-books for free, these can be purchased as well. When trying to gather information books are a very useful source, they can help with revision, presentations or maybe even if you just want general knowledge. At the front of books, you will see a contents page and also at the back of books an index, so it is then easier to find what you are looking for, this also means that you can save yourself some time instead of having to hunt through hundreds of pages for what you want. In some books, some content pages are more detailed and specific than others, that does not mean they are any less useful. Overall, the majority of books are secondary sources, this is where the authors take their primary source and then add their own analysis.
