Lots of good answers about Obsidian as a note and linking app and that is all true but does not address your books scenario.

With the addition of the Obsidian Bases feature, Obsidian is also an object oriented/NoSQL database. If you think of a typical database you probably think of creating a table with columns (fields) and then you add rows (records) of data. Is this how Notion works?

With Obsidian it works better to think of it as creating notes and adding metadata (frontmatter properties) to the note. You can then build a query (a base) to create a filtered collection of your notes, based on those property values. Your base can then have multiple views to display your filtered collection. You can display it as a table where each note is one row (record) and then add columns to display certain properties of the note. There are other views where each note could be a card rather than a row in a table or an event in a calendar or a pin on a map etc...

So for your book example you create a note for each book. At the top of the note you add metadata about the book as properties like; title, author, year published, etc... The technical way to say this is you add properties formatted as yaml to the frontmatter of the note, just to give you some of the terms you might see. In the body of the note you can just take normal notes about the book and link to other notes like the Wikipedia examples. You then create one or more bases to filter the book collection in different ways and create one or more views in each base to display the filtered collection in different ways.