It's been a while since I've been properly delighted by a book.
But I read Penumbra in old-school text-on-a-page format (thanks to James Gross' support of the Percolate library); appropriately, perhaps, given that so much of Penumbra is about printed books.
There's so much about this book I loved: wonky discussions of typography; characters so vividly sketched I could easily imagine having them over for coffee and spirited conversation; a reference to a secret passageway that delighted my inner fantasy-epic-devouring-fourteen-year-old. HackerNews makes an appearance, as does the Googleplex.
I'll cite one of the book's closing epigrams here, because it gives a sense of the life-affirming nature of the work:
“There is no immortality that is not built on friendship and work done with care.”
Go read it. And get it in print. Not just because the cover glows in the dark.
The Amazon link is an affiliate link, which means that if you click through and purchase the book, I'll get a tiny percentage of what you spent - at no cost to you - which I will inevitably use to buy more books.