Free. Everyone gets this.
The Library shows all your books as covers. It’s the Grid tab at the top of Reading Vault.

Reading Vault fills in the title, author and cover from the file when it can. If a book is already in your Library, it tells you instead of adding it twice.
An empty Library shows a card offering four free classics from Standard Ebooks: Meditations, Pride and Prejudice, The Adventures of Sherlock Holmes and Walden. Press Add sample books and they download and land on their own Sample books shelf, so there’s something to read, highlight and listen to right away. The first time you open an empty Library, a short welcome offers the same thing. Free for everyone; the button goes away once you have any book in your Library.

The line under the title tells you how many books you have and how many you’re reading.
Every book has a status: To Read, Reading, Finished or Abandoned. A new book starts as To Read. When you open it, it moves to Reading on its own. You change it yourself on the book’s page. See A book’s page.
At the top of the Library, just under the title, one line shows today’s reading: minutes, pages and your reading streak (“No streak yet” until you’ve read on a day). With Pro it also opens the Reading Dashboard.

Open the book’s page and press Delete this book… at the bottom of the Details box. Reading Vault asks you to confirm first. Deleting removes the book’s note, its file, its cover and all its highlights, so take a moment before you confirm.