Creating accurate charts/graphs in Numbers using separate tables

> Is what I explained above really the only/easiest way to go about creating charts & graphs that display the information accurately?

'Only' and 'Easiest" are not the same thing :)

The ultimate answer depends a lot on what you're trying to get out of this.

Ultimately, Numbers cannot read your mind and intuit how you want to categorize and summarize your data in your charts, so you're going to have to do some of that work to help out.

In addition, it isn't actually clear (at least to me) how you intend/hope to summarize the data - you say by month, but a book reading could span multiple months, like The Body in the Library which you started in August and finished in September. How does that translate to your graph?

Either way, for things like this, it is best to think of it in multiple levels.

The first level (like your first screenshot) is a data warehouse of all your reading history. This can be in any order, it's just a repository for the data you're using.

The second level is the intermediate tables that extract data from the data warehouse. it's up to you what data you want and how you want to structure/format it.

For this level, there are three typical approaches.

One is to add Categories to your data (Inspector -> Organize -> Categories). This will have Numbers categorize the data automatically, and reorder/regroup the rows into logical groups based on the rules you set. It's a simple toggle on/off to apply.

Second is a Pivot Table which is useful for multi-dimensional data. It may be overkill for this, but you could pivot the data into rows and columns, based on multiple criteria (e.g. star rating, by month, by author). Pivot tables are periodic, in that they work on a snapshot of the data based on a point in time. You can update the snapshot at any time as you amend the source data, but it's not automatic.

The Third option is via manual tables, which is what I think you're alluding to in your post. This is the most flexible since you can write a table that extracts the data based on any criteria you set, and format it in any way you want. Takes more work, though.

Note that these tables can be static (e.g. a 'January' table that pulls the rows that have a January date, a separate table for 'February', 'March', etc.), or they could be dynamic (e.g. a popup menu where you choose which month you want to view and it pulls the appropriate data).

Here's a couple of examples of the above, based on this data table I created:

Option 1: Categories:

Category based on Ranking:

Or maybe by year:

Option 2: Pivot table, based on counts of ranking by year:

option 3: manual table:

Literally too many permutations and combinations to consider, but here's a simple table that extracts the MONTHNAME() from the dates in the Data table and displays the counts by rating:

Once you've categorized your data, it's easy to build the graphs, but it really it comes down to what are you trying to achieve and what you want it to look like. Only then can you devise the 'best' path forwards.