Architects often talk about the need to design with an awareness of context, but few architects have taken the issue as literally as Richard Matteson. The Los Angeles-based architect has designed a building that, from certain angles, not only fits in with the surrounding landscape-in this case, a lush forest in a Los Angeles canyon-but from certain angles is well-nigh invisible.

Land use in our society is generally an "either-or" proposition. Any given site is zoned for industry or housing or open space, but rarely more than one use at a time. And we compartmentalize one land use from another by drawing thick black lines on our land-use maps, often in a completely arbitrary way. That thick black line has grown a little thinner on 471 acres of land, nearly half of which lie underwater, owned by Dow Chemical in the city of Pittsburg.

The booklet titled "Accessory Dwelling Unit Manual" may not hit The New York Times bestseller list any time soon. But this unprepossessing little booklet is dynamite because it promotes the least popular type of housing in California.