You must respect copyright laws. If the publisher has granted digital rights or if the book is in the public domain, downloading is permissible. However, many contemporary prints (Darul Uloom Deoband, Maktaba al-Bushra) are copyrighted.
The is typically divided into several massive volumes (depending on the publisher), totaling thousands of pages. It is systematically organized to cover every aspect of the Sahaba’s lives. Hayatus Sahaba Arabic Pdf