Nicholas Roscarrock's ‘Lives of the Saints’ exist in a unique manuscript in Cambridge University Library: MS Add. 3041 (C), of which the first and final sections—about one fifth of the work—are now missing. It has never been printed, except for short extracts and quotations, for which its bulk must be partly responsible; the extant part consists of some 800 pages and would require just as many in a modern edition. The other, even greater, deterrent to those who would edit the work is its character. Roscarrock compiled his book from printed sources and manuscripts, most of which have survived and are readily available elsewhere. The saints he studied, too, have often been more fully and accurately investigated by later scholars. Much of his work is now of value only in showing what an English Catholic writer knew and felt about saints in the early seventeenth century, and what sources were available to him. For the saints about whom he wrote, we would do better to go to more recent literature, and Roscarrock's prose style (which is sometimes long-winded) is rarely memorable enough to make his book worth reading for that sake alone.

The Lives have attracted interest in the twentieth century chiefly for what they have to say about the saints of Cornwall. Here they have a more enduring value because Roscarrock came from the county, had a particular interest in its hagiography, and remembered or collected a good deal of oral information and folklore which does not survive elsewhere. Pending a complete edition of the Lives, it has seemed a sensible and more feasible task to extract from the work the entries relating to the saints whom Roscarrock associated with Cornwall and Devon, as well as those whom we would now associate with the two counties. These entries, totalling about 100, form the core of this work, accompanied by an introduction and notes placing Roscarrock's entries in modern historical context. The volume has a second purpose, which is to shed light on Roscarrock, his book and the times in which he lived and wrote: the late sixteenth and early seventeenth centuries.