Meg Urry's book review 'Myth of the missing mothers' (Nature 458, 150–151; 2009) incorrectly referred to two contributors as the daughters of editor Emily Monosson. They are the daughters of Anne Douglass, a scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Mark Buchanan's book review 'Bringing clarity to complexity' (Nature 458, 411; 2009) incorrectly referred to “the late Jim Crutchfield”, who is still very much alive.

Our sincere apologies to all concerned.