Stephen Hawking co-authored his 1973 book *The Large Scale Structure of Space-Time* with George Ellis.
The book is a highly technical treatise on general relativity, written for specialists rather than general readers. Hawking and Ellis used the mathematical structure of curved spacetime to examine subjects including causality, gravitational collapse, black holes, and singularities.
Its importance lies partly in bringing together developments in global analysis, differential geometry, and relativity. The work helped establish rigorous foundations for studying how Einstein’s theory describes the large-scale structure of the universe and the conditions under which singularities arise.
The other names in the options are associated with Hawking’s scientific network but not with this book’s authorship. Roger Penrose collaborated with Hawking on singularity theorems; James Hartle later worked with him on the no-boundary proposal; and Kip Thorne was associated with black-hole research and later scientific collaborations.