Horror: The Definitive Guide To The Cinema Of Fear is a new book about horror cinema. Not just any book, mind you, but the Definitive Guide (or so it proclaims). Any book with the word definitive in its title is asking for trouble, because the author's idea of definitive may not be the same as the reader's.
In this case, the authors are James Marriott and Kim Newman. Or rather, Marriott is editor and principal contributor, Newman wrote introductory essays to each chapter, and six others wrote reviews and shorter essays. It's rather misleading that Marriott and Newman are the only names on the cover, especially because they are not credited as editors - the cover implies that they are co-authors, which is not strictly true.
Newman is one of the very best writers on horror cinema, and his essays in this new book (overviews of the genre in each decade) are excellent. (He also wrote Nightmare Movies, a comprehensive study of the modern horror film.) It's a shame, therefore, that he didn't write any of the chronological film reviews that make up the bulk of the book.
The format is very clearly modelled on Horror: The Aurum Film Encyclopedia, edited by Phil Hardy. Hardy's more comprehensive book also concentrated on film reviews in chronological order, punctuated by overview essays introducing each decade. (Newman contributed many reviews to the second edition of Hardy's encyclopedia.)