Upon release, the book was met with a positive reception from critics, with praise towards Sampson's complex portrayal of Barrett Browning's life and voicing her importance as one of the leading Victorian poets.

English journalist Lucasta Miller gave the book four out of five stars in her review for The Daily Telegraph, saying that it "restores [Barrett Browning] to her proper place as one of the leading voices of the Victorian era".

[5] While referring to Two-Way Mirror as a "page-turner", The Irish Times's critic Martina Evans described the biography as "passionate and exacting" and wrote that it is a "surprisingly compact volume, a bristling lyrical sandwich of philosophy and action".

[4] Similarly, Brian Morton of The Herald raved about Sampson's portrayal of Barrett Browning's life as a "complex portrait, with its multiple frames and mirror effects".

"[1] Literary Review's Claudia Fitzherbert praised Sampson for crafting an "absorbing study of [Barrett Browning]'s risk-taking and originality as a poet, covering ground missing from Margaret Forster's biography published in 1988.