Walsh's book on this subject is arguably the best non-scholarly work available, better even than Professor Guarducci's own book (published in English translation in 1960 as "The Tomb of St Peter"). Walsh did his homework, writes clearly, provides helpful diagrams and interesting photographs. There are also references and bibliography which enable a more curious reader to pursue the subject further. Readers who have been conducted through the "scavi" beneath St Peter's will find this a wonderful clarification of what they saw, those who plan to visit them will find it an excellent preparation. But, a very strong warning. The electronic text is horribly riddled with typographical errors, at least one or two per page. Some of them are easy to decipher, and almost funny, e.g., "Pope Pius XH's admitted personal fascination" or "Imagine an immense square shaft ... twenty 'jam feet on a side." Others so badly mangle words and numbers that it is impossible to decipher the original, sometimes important, word or date. That readers should have to engage in such an exercise does no credit to the publishers, and if it is at first an annoyance, it soon becomes distracting and frustrating. If you really want to read the book, you'll be happier with a bound copy.