How I Use Luminaria to Build My Second Brain

For a long time, my reading and my thinking lived in completely separate places. On my Kobo: hundreds of highlights, carefully marked, sitting in the dark. In Obsidian: a growing vault of notes, ideas, and half-formed thoughts that never quite connected to what I was actually reading. The two systems didn't talk to each other, and that gap was costing me more than I realised.

Building the Luminaria Obsidian plugin was the thing that finally closed it. Now every highlight I make on my device ends up in my vault — automatically, in its own file, properly structured — and my note-taking has changed in ways I didn't expect.

The problem with highlights that go nowhere

I've always highlighted heavily. It's how I read — pencil in hand, or in the case of the Kobo, a tap on any passage that stops me. But highlighting is only half the process. The other half is returning to those passages, connecting them to other ideas, letting them do something.

That second half almost never happened. The highlights stayed on the device. I'd occasionally open Luminaria to browse them, and the rotating quote on the homepage would surface something I'd forgotten. But they weren't in my vault, they weren't linking to my notes, and they weren't becoming part of how I actually thought.

The concept of a second brain — a personal knowledge management system that captures, organises, and surfaces everything you've learned — only works if the inputs are actually getting in. For readers who use e-readers, highlights are often the richest source of raw material. If they're stuck on the device, the second brain is running on a fraction of its potential.

What the sync actually produces

When Luminaria syncs to Obsidian, it creates one markdown file per book inside a folder of your choice — I use a folder called Luminaria in my vault root. Each file has YAML frontmatter at the top with the title, author, tags, and the date it was last synced. Then the highlights follow, grouped by chapter heading where available, with the page number and date highlighted as metadata under each one.

The structure matters more than it might seem. Because Obsidian can index frontmatter properties, every book I've read becomes searchable and filterable. I can see all my highlights tagged with luminaria, sort by sync date to find recent reading, or filter by author. The vault becomes a proper library, not just a folder of text files.

How it fits into my actual workflow

My workflow now has two distinct phases. The first happens on the Kobo — I just read, and I highlight anything that resonates. No friction, no interrupting the reading to take notes. Just marks on the page.

The second phase happens in Obsidian. When I sit down to process what I've read — which I try to do within a day or two of finishing a book — the highlights are already there. I don't have to export anything, copy anything, or type anything out. The raw material is waiting.

From there, my process is simple. I open the book's file in Luminaria's Obsidian folder and work through the highlights. Some I leave as-is — they're context, background, passages I marked because they were well-written rather than because they sparked a thought. Others I turn into permanent notes: a short file in my main notes folder that captures the idea in my own words and links outward to related concepts.

The highlights file itself becomes a kind of index. I'll often link from a permanent note back to the specific highlight in Luminaria's folder that prompted it. That link creates a trail — from the raw highlight, through the idea it sparked, to wherever that idea ended up going in my thinking.

The connections I wasn't making before

The most unexpected benefit has been the connections that surface through search. Obsidian's graph view and full-text search now span my entire reading history, not just my intentional notes. When I'm writing something about a topic, I'll often search the vault and find a highlight from a book I read two years ago that's directly relevant — something I'd completely forgotten marking, now surfacing at exactly the right moment.

That's the thing about a second brain that actually works: it's not just storage. It's retrieval. The value isn't in capturing ideas, it's in getting them back at the moment you need them. Having highlights in Obsidian rather than on the device makes the difference between a thought that's archived and a thought that's active.

There's another dimension to this that I've only recently started exploring. Because the highlights are now plain markdown files in a vault, they become accessible to AI tools that can read from Obsidian — including Claude via the Claude desktop app, which can be given access to your vault as a knowledge source. Asking Claude a question and having it draw on three years of your actual reading — not the internet's reading, yours — is a qualitatively different experience. It's your thinking, extended. The highlights are the raw material; the AI becomes a way to query and connect them at a scale that would take hours to do manually.

The sync itself is invisible

One thing I want to emphasise because it matters for how sustainable any system is: the sync is completely automatic. With the KOReader plugin installed and a Premium subscription, my highlights sync to Luminaria every time my Kobo connects to WiFi. The Obsidian plugin picks them up on vault startup. By the time I sit down to process, everything is already there.

I didn't used to trust myself to maintain manual export workflows. I'd do it diligently for a few weeks and then stop, and the gap between what was on the device and what was in my vault would grow until it felt too large to bridge. Automation removes that failure mode entirely. The system works whether or not I remember to tend it.

A note on the second brain concept

The idea of a second brain — popularised by Tiago Forte's Building a Second Brain — is sometimes treated as a productivity system, a way to be more organised or to get more done. I've always found that framing a bit thin. For me it's more about something older: the commonplace book tradition, where readers for centuries collected passages, ideas, and observations not to be productive but simply to think better.

Highlights are the modern version of that. They're the passages you wanted to hold onto, the moments where a book said something true or surprising or useful. Getting them into a system where they can link and accumulate and resurface is just taking the practice seriously.

Luminaria started as a way to browse those highlights beautifully. The Obsidian sync turned it into something more — the first step in a reading workflow that actually produces something beyond finished books.

James

Former privacy lawyer turned general practitioner. Avid reader. Builder of Luminaria.