How to effectively manage ebooks using Calibre?

Question

I started using Calibre and I'm unable to decide how to effectively use it to manage my ebooks.
I've a huge collection of ebooks organized by subject into folders like Political Science, History - World, History - US etc. Till using Calibre, these folders were synced across all of my devices (Android phone, tablet, desktop) using Cloud storage. In this way I could browse any subject anywhere using either browser or file explorer or in android phone.

But when I have added the collection to Calibre, it has destroyed this folder structure and made it one folder per author. If I'm syncing this library using cloud storage, I've no way to know which are History books and which are political science books.

What is the effective way to manage books using calibre?

Answer 1

Calibre organises the books that way, there isn't much you can do about it. If you want to use it, you must accept that folder structure.

Anyway, books are better categorised by using tags and other metadata informations.

Beside that, Calibre can also run as a web server, providing a website-like interface that you can access from every browser. Obviously, to use this feature, Calibre must be installed on a machine that is always on and connected to Internet.

Answer 2

As written in the Calibre manual you should use tags:

But suppose you want to find all unread science fiction books. There’s no easy way to do this with this folder scheme, [...] In calibre, you would instead use tags to mark genre and read status and then just use a simple search query like tag:scifi and not tag:read.

It might take a while to get everything properly tagged, but after that it will be easy to find what you want.

Answer 3

As the accepted answer, Calibre or Calibre-web can not meet the requirement specified in question.

But after 7 years, Kavita https://github.com/Kareadita/Kavita seems to meet this requirement, which is a Plex(a popular home media server) sytle manga/comic management server. It works with epub, pdf, cbz, cbr.

Instead of uploading or importing book/manga/comic to it, you have to first setup a file directory with contents on disk. Then you create Library in Kavita and point it to the folder on disk. The folder is scanned and Kavita will analyze the folder structure, file name syntax and show them in its browser interface. It defined some naming rules you should follow https://wiki.kavitareader.com/en/guides/managing-your-files/comics. Except for that, Kavita don't touch folders and files on disk.

I have used it for a while, it may not be the best solution for all your ebooks, especially when you have lots of ebook in different type such as epub, mobi, azw, etc. Mobi and azw files are ignored and not show up in web interface by now. But it is very useful if you just want an easy way to access books your are reading and a lightweight management tool for books.

Answer 4

According to some valuable feedbacks I modified my answer:

The Same Problem:

I had more than one Calibre libraries since I have imported the e-books' folders from my computer as libraries. I wanted to combine those libraries as one (merge) but I wanted to maintain the folders' hierarchy or at least I wanted to organize and see the e-books as if they are in the corresponding folders.

My Solution:

1. Create an empty library. Name it anything but this will be the one and only your Calibre Library. Of course you can rename it in Calibre later.
2. Create a custom column from "Preferences -> Add your own columns -> Add custom column -> Comma separated text, like tags, shown in the tag browser" by adding lookup name and column heading. Column heading will be used to enter the name of the merging library (that is your folder name).
3. Copy your e-books in the existing library to the one created in 1. Let's call it main library or anything you want.
4. Without copying other library, select all the e-books and edit metadata. In the "edit metadata" window you will see a second tab "custom metadata" where your lookup name appears. Fill the blank as the corresponding library name (that is your folder name).
5. Now on the Calibre left column you will see your custom column and its subgroup as your added library (that is actually your exported folder name exported as library).
6. Repeat the same process for other libraries from number 3 to number 5.
7. You will now have your special column and all the different libraries as subgroups. You will have one Calibre library with different subgroups. This is powerful than using tags for this purpose since subgroups are your choice of organizing your e-books.
8. Since I had many Calibre library, I tried to merge them copying one by one. You may have many folders of e-books each organized in your way. You can add your e-books one folder by one folder using the process explained from 3 to 5.
9. At the end, you will have one Calibre library with different subgroups on the left panel. Subgroups will be anything you want, for example your e-books' folder hierarchy in your PC or Mac.

The original answer was: "I wanted the same. I preferred the following solution; https://manual.calibre-ebook.com/sub_groups.html"