We Are Water says it's about "human resilience in the face of tragedy" and I'd say that's an apt description of his writing in general.
We Are Water is grand in scope. Lamb tells the story of the Oh family the only way you can: through history. The story alternates narrators, giving the reader a broader perspective. The characters tell us about their childhoods -- the Japanese immigrant grandfather, the mother who died in a flood in 1963, the unknown man whose art inspires in the present -- all of this gives context. The stories intertwine in surprising ways.
There are some things to criticize here. Sometimes Lamb gets overly detailed and repetitive; this novel was over six hundred pages and could have withstood a few killed darlings. Also, I would have preferred fewer graphic descriptions from the pedophile and a less over-the-top dramatic climax.
For me, the joy of fiction is always the characters and Lamb is an expert at creating full and complicated characters you fall in love with. I recommend this book.