[PuffinBlue]

I have a somewhat similar system but without writing anything in the book, because I use ebooks, and it's not quite as intensive.

An example is here[0] but basically I keep notes on:

Places

Things

Characters

Plot

Nothing too long and it's all filled in in a few seconds in an Evernote notebook/note as I read along.

The main reason this is effective for me is that I can very quickly look up a character/place/plot in one single place in just a few seconds.

Often I don't need to re-read the whole thing, just the 'recent past' bits to quickly remember where I was in the plot after I put the book down for a week or two.

It ends up looking like a lot but it's more a consequence of doing a little a lot of times rather than a large amount of burdensome work.

I'm not sure if it helps long term retention, but it does help short term and it certainly helps comprehension when I've forgotten some characters significance or minor but consequential plot point.

[0] https://www.josharcher.uk/blog/diaspora-greg-egan-book-revie...

[elboru]

I decided to do something similar after reading a Chinese Sci-fi novel (The Three Body Problem) it was a really cool novel but I found it difficult to retain a lot of the characters' names, I had to go back in the book several times looking for names and that made the reading a little tedious.

[maaaats]

Kindle has this as a feature called XRay. Can click a name for instance, and quickly see relevant info so far.

[PuffinBlue]

I don't really want anything to do with connecting the Kindle to the internet. Mine has never been off airplane mode and books are transferred by USB so xray isn't very useful to me. Also it means I can't simply scan over the notes to see catch up.