Security isn't just about stopping police of fash from harming us from the outside, but also about keeping our movement resilient from within. "Why Misogynists Make Great Informants" is very important to read as misogyny isn't just awful on its own, but it enables informants and destroys our movements.
https://archive.org/details/WhyMisogynistsMakeGreatInformants/mode/2up?view=theater
Related bonus that pairs well with this but isn't strictly about security. Betrayal: A critical analysis of rape culture in anarchist subcultures
"Stop Huntin' Sheep" is a fantastic text on concrete methods for creating robust networks from which to take action, small or large. Like "Confidence," this zine discusses how to positively build a network instead of hoping to kick out everyone with the wrong "vibes."
https://www.sproutdistro.com/catalog/zines/security/stop-hunting-sheep/