Building a Second Brain

Context

I had started this book earlier in 2025 and not finished it. Coming back to it in Ibiza, in a different environment and after several days of more conceptual reading, the practical elements landed more clearly than they had the first time. That itself felt relevant — the context in which you engage with something genuinely changes what you take from it. The same material, read in more fragmented conditions, had produced a different result.

What Stuck

The "box" concept stayed with me more than any specific system the book describes. The insight is that creating a defined space for something before it is fully formed changes how you begin. Instead of waiting until an idea is understood well enough to be shared or acted upon, you create a place for it and let it develop there.

That is a subtle but meaningful shift. It changes the activation energy required to start. It also changes the relationship between thinking and doing — making them more concurrent rather than sequential.

Application

I have applied this more broadly than the note-taking context the book is written in. It applies to projects, to problems I cannot yet articulate clearly, and to observations I want to follow up on without yet knowing where they lead. The system creates permission to be in-progress, which is a more honest description of how most good work actually develops.

The week in Ibiza also made the value of this more visible. With less fragmented time and more space to follow a thought fully, I could see clearly what the system was trying to compensate for in normal working conditions.

Reflection

The book is more prescriptive than I typically find useful — the specific system it proposes works well for the author's way of working, which will not be everyone's. But the underlying principle is sound. The value is in taking the idea of externalisation seriously and finding the version of it that works for how you actually think. Read in that spirit, rather than as an instruction manual, it is genuinely practical.