

His Dark Materials
Singularity Sky (and its sequel, Iron Sunrise)
Harry Potter and the Methods of Rationality (a fanfiction novel that is far better than the original series)
What If (and What If 2, by Randall Munroe)
The Planiverse
The Knowledge: How to Rebuild Society After an Apocalypse
Sophie’s World
Kim Stanley Robinson’s Mars trilogy
Helsinki. Seems like a fairly decent place.