Hello Kovil.
I have been using Calibre E book to manage my e book collection for several years now. First of all, let me say it is a great tool and thank you for all the work that you and your team constantly put into enhancing its features and usability. Additionally I also use Kindle to manage some e books.
I write to make one very heartfelt recommendation. I mainly read non fiction in order to do research and write about certain topics, therefore, in order to highlight and make annotations {and save them}, I constantly have to convert my e books into PDF or use Kindle.
Unfortunately, these tools are absent in the Calibre E book viewer. If these tools were included in E book viewer, my need of PDF and Kindle would drop significantly. I personally think that including said tools would greatly increase the growth, usability and functionality of Calibre in general and Calibre's E book viewer in particular. Notwithstanding, I am a fan of Calibre and will remain being one, I just thought I just should let you know about this concern that others have too.
Thank you very much for all the hard work and for the time it took you to read this letter.
Best Regards.
Mike.