The *Book of Jasher* is a pseudepigraphal expansion of biblical history, presenting an enlarged narrative from creation through the period of Israel's judges. Its episodes elaborate briefly reported events, supply speeches, genealogies, battles, and moral reflections, and give legendary figures such as Abraham, Moses, Joshua, and David greater dramatic and psychological presence. Written in a chronicle-like, scriptural idiom, the work imitates the authority and cadence of the Hebrew Bible while blending saga, ethical instruction, and folkloric embellishment. Although cited in Joshua 10:13 and 2 Samuel 1:18, the surviving text is not part of the Jewish or Christian biblical canon and should be read within the complex tradition of later biblical pseudepigrapha and religious literature. The author is anonymous, and the book's precise date, provenance, and original language remain subjects of scholarly debate. Its claim to preserve the ancient "Book of the Upright" mentioned in Scripture reflects a longstanding practice of attributing later compositions to venerable sources in order to interpret, supplement, and imaginatively inhabit sacred history. The text therefore reveals as much about the devotional and literary interests of the community that transmitted it as about the patriarchal and national past it portrays. Readers interested in biblical reception, Jewish and Christian pseudepigraphy, and the development of sacred legend will find the *Book of Jasher* especially rewarding. It should be approached critically rather than as an authenticated historical record, yet its expansive storytelling offers valuable insight into how later communities filled narrative silences, shaped exemplary character, and continually reinterpreted the Bible's foundational stories.