E-books are electronic books or digitalbooks that consist of content in text, image and tabular form. E-books are published electronically and can be read on electronic devices like smartphones, e-book reader and tablets. They can be categorized into two parts - open source ones, whichusers can download freely and those for which users have to pay. Paide-books require special software and applications with the help of which they can be read.These books are available in various formats such as .odf, .txt, .pdf, .html, .lit, .epub, .prc, .dnl, .mobi, .azw etc. In order toread e-books on electronic devices, users are required to install specific software or appbased on compatibility withe-book formats. For example,the .azw e-book formatcan only be read on Amazon Kindle software. E-booksare used for e-newsletters, e-journals, e-magazines and so on.In recent years, several e-book providers have adopted the e-book formatting technique by using HTML and CSS tools. In addition, e-bookpublishers concentrate on the e-book file size compression, to enable their customers to download the e-books easily and read it with minimum configuration requirement.