2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/63184Let $T$ be a Fourier integral operator on $\R^n$ of order $-(n-1)/2$. It was shown by Seeger, Sogge, and Stein that $T$ mapped the Hardy space $H^1$ to $L^1$. In this note we show that $T$ is also of weak-type $(1,1)$. The main ideas are a decomposition of $T$ into non-degenerate and degenerate components, and a factorization of the non-degenerate portion.17 pages, no figures, to appear, J. Aust. Math. Soc. Minor grammatical changes and some more references addedClassical Analysis and ODEs42B20text