Though there is some excuse for Calibre as it's at least:
- A Library / Database to manage your ebooks
- An advanced full text content search system for research
- An ebook viewer
- An ebook editor, inc ToC creation/editing and more.
- Manage devices and transfer to or from them, inc user templates.
- Edit Metadata.
- Create or add covers
- Search Internet for covers or metadata.
- Convert between many ebook formats.
- Manage annotations from devices (Kobo Utilities or Annotations)
- Well supported 3rd party plugins for many features*.
- Supports all three main OS for desktops/laptops
- A server that provides a web interface and OPDS.
- Can create catalogues as ebooks
- Better docx to epub than expensive "rent only" Adobe InDesign
It's beyond a Swiss Army knife or tool box but a virtual digital version of the library in a mansion (not a lending library) with a workshop and expert bookbinders, librarians, researchers, secretaries and butler. However it doesn't actually serve drinks.
A multi-tool where each blade or part can be a multi-tool!
Thanks Kovid. It's up there with web Browser, spreadsheet, wordprocessor, email and image editor for anyone that writes, reads or publishes as a "must have" application.
[* What's in this cupboard? Oh, fantastic!]