People can lose their lives in libraries. They ought to be warned.

Bellow’s line plays on the double meaning of “lose their lives”: one can literally waste away, but more pointedly one can forfeit a lived, embodied existence by retreating into books. The library becomes a symbol of seductive, endless inwardness—knowledge, scholarship, and imagination so absorbing that they can displace action, relationships, and risk. The mock-serious tag “They ought to be warned” adds comic bite while implying a genuine ethical concern: reading is powerful, but it can also become a refuge that turns into a trap. The remark fits Bellow’s recurring tension between intellectual life and the demands of actual experience.