What a long title for such a short book! A short book – but not an easy one. Ahrens is clearly an academic and this heavily footnoted book, full of citations and references, actually tells a simple story.

It’s the story of Niklas Luhmann, a German academic who was known for being incredibly prolific. He published 58 books and hundreds of articles during his 30-year academic career — and his work is considered to be serious intellectual work at the highest level. How did he do it? Luhmann used a system known as the “slip-box” — basically a lot of short notes that referenced one another.

That system has become the flavour of the month among personal productivity geeks who are ready to move on beyond “getting things done (GTD)”, the “seven habits”, “eat the frog” and the others. To give it its proper, German name — making the system sound more exotic and geeky — Luhmann’s system is called “zettelkasten” and there are web pages galore that give a more concise explanation than this book (e.g., this one: Create a Zettelkasten for your Notes to Improve Thinking and Writing • Zettelkasten Method.