Katniss says that she got the idea from her family's plant book, where she and her family write down the names of plants that can be used for healing and eating. Each entry in the memory book contains a photo or if there wasn't one, a sketch of the person drawn by Peeta, and a page of memories that shouldn't be forgotten about them (for example, Rue's arms extended like a bird, Mr. Everdeen's voice, etc.).
The people remembered includes Prim, Mr. Everdeen, Mr. Mellark, Finnick Odair, Cinna, Boggs, and Rue. Haymitch, eventually helps, adding twenty-three years worth of children that he mentored. Katniss and Peeta seal the pages with saltwater (implied to be tears) and vow to live well to avenge the deaths of the people in the book.