For an introductory textbook, you'd do better with Shan Winn's "Heaven, Heroes and Happiness: The Indo-European Roots of Western Ideology." Puhvel's volume started life as a series of classroom lectures, and I suspect that unless you did the assigned reading beforehand (presumably the books listed at the end of each chapter), you'd be left baffled. Summarizing the vast body of ancient Indo-European myth, as Puhvel does for most of the book, is a slog: a long list of names, attributes, battles and recurring motifs that need to be put into context, which he does to a certain extent in the brief final chapters.
It's not like Puhvel doesn't recognize the source material's problems. In recounting the 18-day battle that's the centerpiece of the Mahābhārata, he notes that one of the commanders "is cut down by a shower of arrows. He thus makes use of his privilege to die on his own terms, and emphatically so, for he is not yet through: Propped up on the arrows that penetrate his body, he watches the rest of the battle like a reclining Saint Sebastian and waits for his turn to fill up books 12-13 with his interminable Mirror for Royalty; compared with this longest deathbed sermon on record, Homer's long-winded old man Nestor was a paragon of laconism."
There's more! The Old Iranian Vivēvdāt collection of religious texts is "a surprisingly rewarding document for comparative mythology, considering that much of it is a dreary, even revolting piece of preoccupation with uncleanness and pollution, with vicious beatings as a cure-all for most aberrations, including a woman's irregular menses." I wonder what he'd write about the Priestly strand of the Hebrew Bible.
Here's another quote: "In a way Odin is in a bind; in Germanic theology he epitomizes what is called in German die Not der Götter, the cosmic crisis that foreshadows the world cataclysm. ... In his hour of need (the etymological cognate of Not) he is even a figure of some nobility and certainly of pathos, at least in the modern German Wagnerian representation." To which he adds: "h-e-i-l-i-g-e N-o-t is impossible to replicate in English, 'holy distress' would sound too much like Batman." Moments like that earned the third star.
Finally, a couple of detours into Fun Fact territory: (1) The Gaulish "belief in an afterlife was strong, for Gauls would lend money on terms of postmortem reimbursement," and (2) there are striking similarities between the Mahābhārata's story of the king Yayāti and his children and, in Genesis, the account of Noah and his sons' actions after the flood. Imagine the delight of the Biblical minimalists who think the so-called J and E texts date from the Exilic or post-Exilic periods, when Semitic and Indo-European mythologies met head-on.
Those are the book's highlights, but most of it is tough going. If TV Tropes ever gets around to doing Indo-European mythology, it would be a godsend.