Burrowed into a mountain outside of Salt Lake City are vaults holding an historical treasure of staggering size. Over one million, 100-foot rolls of filmed manuscripts—with the number growing rapidly—from forty-two countries have been collected by the Genealogical Society of Utah. The Mexican holdings total 105,584 rolls of film, about one-tenth of the entire collection.

The Preliminary Survey of the Mexican Collection (the first publication in a series entitled Finding Aids to the Microfilmed Manuscript Collection of the Genealogical Society of Utah) introduces the Mexican holdings with the specific intention of giving scholars a clearer picture of what is available and what is not” (p. xix). Given the immense size of the collection, the book succeeds in an admirable way.

The introduction describes the extent of the collection, emphasizes the diversity of documents, and repeatedly demonstrates that there is much of interest to more than just demographers and genealogists. Materials other than parish and civil records are abundant, running from 10,000 to 20,000 rolls. The numbers prove that this part of the collection is enormous, but also show how little is known about it. By briefly describing some of the documents and their archival provenance, the authors do give something of the flavor of the holdings. Examples include 1,551 volumes of Inquisition records from the Archivo General de la Nación, and an “apparently complete” (p. xxix) run of Guadalajara notarial records from 1600 to 1900.

These riches form only the sinew of the collection. The meat is the civil and parish registers. It is here that the guide is an indispensable aid to Mexican scholars. Organized by state and municipality, it gives the number of rolls and dates covered for each municipality. The availability of documents other than parish and civil registers is also noted. An added bonus is a list of census materials, once again organized by state and municipality. With one flip of the thumb, the researcher can now find out how many rolls of film are available on a specific location.

The survey is a welcome addition to the spare literature on the holdings of the Genealogical Society of Utah. It will certainly stimulate interest in the collection, and hopefully the interest will lend speed to the publication of more Finding Aids.