Although the Prestons' book is well written, only a portion of it delivers what its title and cover seem to promise. This, of course, you will quickly discover if you have a copy to preview. If you don't, you should know that much of the book focuses on the struggles to gain/keep territory and the throne over the course of almost two centuries and six shahs. There is also much information about various shahs' idiosyncrasies and addictions, their strengths and weaknesses as leaders, and the customs of their courts and harems. What 3/4ths of the Prestons' book is really about, in fact, was equally well covered in the aptly titled A Brief History of the Great Moghuls, reprinted in 2002.
It is difficult to rate the approximately 60 pages of text in the Prestons' book that do focus on the Taj complex, including its antecedents, the people directly involved in its construction, its ornamentation, the toll time has taken on it, and a chapter on the theory that Shah Jahan had planned a different mausoleum for himself. Those who are reading about the complex in depth for the first time will likely find the material interesting; those who have read other books on the subject are unlikely to find much that is new.
Unfortunately, it is not at all difficult to rate the 23 snapshots of the Taj complex and related funerary architecture in this book. First, most are small, grainy black and grays that reveal little more than general outlines. Second, even the seven in color (four of them small ones of interior details) are taken from too great a distance to reveal technical brilliance or artistry. That only the cover and another mood shot of the mausoleum appear to be the work of a professional is a major weakness in a book that purports to be about the genius of the Taj Mahal, for only superb photography can truly convey much of it. As for drawings to illuminate structural detail, the only two merely shade in an arch and a vault.
For the reasons noted above and more, if you are interested in India's national treasure, you will do yourself a great favor if, before deciding on the Prestons' book, you investigate the following: 1) Okada, Joshi & Nou's Taj Mahal (1993), a visually stunning and informative book and 2) E. Koch's The Complete Taj Mahal (2006), a TEN-STAR BOOK that "should be in the library of anyone fascinated by the Taj Mahal, not just historians and architects." (Incidentally, that the Prestons' bookcover is almost identical to Koch's does not make their book comparable to hers.)