There exist multiple good, free encyclopedias of philosophy online: https://plato.stanford.edu/entries/life-meaning/#Nihi https://plato.stanford.edu/entries/li

There exist multiple good, free encyclopedias of philosophy online: https://plato.stanford.edu/entries/life-meaning/#Nihi https://plato.stanford.edu/entries/life-meaning/#Nihi https://www.rep.routledge.com/articles/thematic/nihilism/v-1 https://www.rep.routledge.com/articles/thematic/nihilism/v-1 https://iep.utm.edu/nihilism/ https://iep.utm.edu/nihilism/ Stanford's is probably the best-regarded of the bunch—you'll struggle to find a better brief introduction to most topics, than it provides, especially for $0. Skipping e.g. Wikipedia and going straight to the SEP, for philosophical topics, is usually a good call.