Who We Lost is the first book that directly acknowledges the free-floating grief of the COVID-bereaved, affirms that it must be addressed, and offers a purposeful activity that respects mourners as well as the mourned.

In 2020, Martha Greenwald invited mourners to write memories of loved ones lost to COVID on the Who We Lost website. The site has been growing ever since, as the bereaved continue to write and publish stories, and the writers' toolbox section of the website offers guidance and prompts for anyone wishing to contribute their story about who they lost to this grassroots public memorial.

The resultant book, Who We Lost: A Portable COVID Memorial, contains dozens of essays and a writing guide for those wishing to add their own story about a loved one who died from COVID. It is a community-generated tribute, a eulogy, a handbook, and a collective memorial.