NMLP P-022797 · True-first precedence · minted 2026-07-04

Light Thickens

Ngaio Marsh · Collins (Crime Club) · 1982

Marsh died in February 1982 and both the Collins UK and Little, Brown US editions are dated 1982; because Little, Brown accepted the manuscript in her lifetime and precedence for her late novels is not uniformly UK-first, treat the Collins printing as the UK first and confirm global precedence per title rather than assuming it.

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New Mexico Literacy Project — True-first precedence NMLP P-022797 for "Light Thickens" by Ngaio Marsh (https://newmexicoliteracyproject.org/id/point/p-022797, CC BY 4.0, dataset DOI 10.5281/zenodo.21184548).