The Gunslinger → The Drawing of the Three → The Waste Lands → Wizard and Glass → (The Wind Through the Keyhole) → Wolves of the Calla → Song of Susannah → The Dark Tower. The Wind Through the Keyhole is a companion novel set chronologically between books 4 and 5 but published last.
Yes — extensively. The Dark Tower series is King's 'meta-universe' that connects virtually all his other work. References appear to The Stand, It, Insomnia, Black House, Salem's Lot, and many others. Most connections are background texture and don't require reading those books first.
Yes. The Gunslinger is the most experimental and difficult book in the series — King was 22 when he started writing it. Most readers say it's worth pushing through to The Drawing of the Three, which is where the series truly finds its voice. Some readers even recommend reading The Drawing of the Three first.
