Before 1929 the Canaanites were known chiefly through their enemies. The Hebrew Bible polemicises against Baal and Asherah at length, and Greek writers preserved a late and heavily reworked account. Neither is a description of the religion on its own terms.
Then a farmer at Ras Shamra on the Syrian coast struck a tomb, and excavation uncovered the archives of Ugarit: a Late Bronze Age city with a scribal quarter, writing an alphabetic cuneiform in a Northwest Semitic language closely related to Hebrew. The Baal Cycle, Kirta and Aqhat came out of it, along with ritual texts, pantheon lists, offering records and letters. A religion that had been visible only in caricature became readable in its own words within a single generation of scholarship.
The limits are real. Ugarit is one city, at the northern edge of the Canaanite world, and its archive dates to a few centuries before that world ended. Extending Ugaritic evidence southward to Iron Age Canaan or to Phoenicia is an inference, not a reading.
The tablets themselves are damaged, the poetic vocabulary is difficult, and the order of some tablets in the Baal Cycle is disputed, so translations differ on more than style.
For the later Phoenician and Punic phases the evidence shifts back to inscriptions, dedications and classical testimony, and the picture thins again.