cell.com/issue/S0896-6273(25… On the cover: In this issue of Neuron, Du et al. @DuSiling show that repeated microglial depletion enables peripheral monocytes from both the blood and skull bone marrow to infiltrate the brain and engraft as monocyte-derived macrophages with distinct identities. Inspired by a passage from the Zuo Zhuan (“The first beat of the drum rouses the soldiers’ spirits; the second weakens their resolve; by the third, they are exhausted”), the artwork depicts three rounds of microglial depletion gradually exhausting the endogenous microglial niche. The two advancing armies represent distinct peripheral sources of invading cells: one arriving from the blood, illustrated by the army bearing the red flag, and the other emerging from the skull bone marrow, portrayed as descending from the mountains. Artist credit: Ying Xu.