Breviarium Aberdonense (hereafter BA), published in Edinburgh in 1510 (NS), is the most important collection of information we have about Scottish saints' lives, as well as having the distinction of being Scotland's first full-scale printed book. The Propria Sanctorum at the end of each of its two volumes contain prayers and lectiones, lessons or readings, to be read out during the office on each saint's feast day at Matins; in some cases these are interspersed with proper canticles, especially where the saint was patron of a cathedral or other important church. The readings are without exception short and do not constitute a complete vita or life of the saint in question; but in many cases they are demonstrably based on earlier and fuller materials. BA is by far our greatest collection of Scottish hagiography. For many saints it provides our only information, while for others it presents significant variants on traditions which are recorded elsewhere. Even in those instances where it does not provide lessons, it may have brief notes on the cultus of some saints together with a collect for their feast day. And in spite of its late date, BA is important because it records many earlier traditions which have otherwise been lost. Preliminary research into the question suggests that where BA's compilers had earlier materials on which to draw, these are often twelfth-century or in many cases even earlier. As such, BA becomes one of our most important literary and historical sources for the Scottish church prior to the late twelfth century.