Ayn Rand poses theatrically in her signature cape and gold dollar-sign pin on the cover of a groundbreaking new biography. Rand also poses theatrically in this same Halloween-ready costume (Rand impersonators have been known to wear it) on the cover of another groundbreaking new biography. The two books are being published a week apart. And both have gray covers that make them look even more interchangeable. Yet Rand, whose Objectivist philosophy is enjoying one of its periodic resurgences, loathed the very idea of grayness. She preferred dichotomies that were strictly black and white.

So in a Rand universe  like those of “The Fountainhead” and “Atlas Shrugged,” the doorstop treatise-style novels that have given her such staying power  it would be unacceptable that one of these books would be only moderately better than the other. And the versions of her story should not overlap as vastly as they do.

But both authors, Anne C. Heller (“Ayn Rand and the World She Made”) and Jennifer Burns (“Goddess of the Market: Ayn Rand and the American Right”) make many of the same points and touch on many of the same biographical details. That repetition is especially surprising since Ms. Burns had access to the supposedly crucial Ayn Rand Papers at the Ayn Rand Institute in Irvine, Calif. Ms. Heller did not.

Still, Ms. Heller’s research is more intensive. It is so thorough, in fact, that it seems to inform Ms. Burns’s parallel but more cursory account of Rand’s personal life. (The Heller manuscript has been in circulation for long enough to be cited in one of Ms. Burns’s footnotes and included in her bibliography.) Ms. Heller has delivered a thoughtful, flesh-and-blood portrait of an extremely complicated and self-contradictory woman, coupling this character study with literary analysis and plumbing the quirkier depths of Rand’s prodigious imagination. Ms. Burns glosses through all this to arrive at her book’s best section, a lengthy coda about Rand’s intellectual and political legacies. Neither book is the work of a slavish Rand devotee.