She starts with early relations between the British Crown and Maori and pre-Treaty notions of Maori sovereignty. She describes in detail the Waitangi signing itself and the protracted collection of additional signatures. And she surveys the controversies over the text variants and translations, the extent of Maori comprehension, and the role of missionaries.
This part forms a coherent story, but once the Treaty moves from centre stage its course becomes braided. The Treaty was inextricably interwoven with the broader early history of New Zealand, playing a key role in conflicts between governors and settlers, between factions in Britain, and between different groups of Maori, as well as between Maori and Pakeha. Conflicts centred on the Crown's right of preemption over Maori land sales, land rights more generally, mana and sovereignty, which were also at the heart of the wars of the 1860s.
Pakeha and Maori understandings and perceptions of the Treaty continued to diverge. The Treaty "receded from settler consciousness" and "public opinion to Maori grievances cooled further". Maori attitudes varied, but the Treaty played a key role in attempts to recover lost rights and maintain autonomy, including direct appeals to the Queen, missions to Britain, and the Kotahitanga parliament movement. Orange's final chapter sketches the history of the Treaty from 1890 onwards; this is dated now, but the recent history of the Treaty is well documented elsewhere.
The Treaty of Waitangi assumes a background knowledge of Maori and New Zealand history. It makes no attempt at comparisons with treaty-making and British colonial relationships elsewhere. And it's quite dry. So its primary audience will be New Zealand historians and history students; others may prefer Orange's shorter The Story of a Treaty.