The book is published by Spanish art and design publisher Actar and is available for sale on their website.
The images shown are taken from the book while below is some info from the publisher:
Kazuyo Sejima, Ryue Nishizawa
From conceptual drawings to photos of completed projects, [this is] SANAA’s latest and most up-to-date publication. This book is the first collection of housing projects by SANAA, one of today’s most innovative architectural offices. Presenting SANAA’s housing projects, both finished (including House A, S House, House in a Plum Grove, Small House and Moriyama House) and projects in progress (including Flower House, Garden & House, Seijo Apartments, Ichikawa Apartments, House in China).