The volume now published contains the second of the three books into which the history of Scotland during the Celtic period has been divided, and, like the first volume, forms a substantive work in itself. It deals entirely with the history of the old Celtic Church, and its influence on the culture of the people. The early ecclesiastical history of Scotland is a subject beset with even greater difficulties than those which affect its early civil history. It shares with the latter that perversion of its history which has been caused by the artificial system elaborated by our oldest historians. The fictitious antiquity given by it to the settlements of the Scots is accompanied by a supposed introduction of Christianity at an earlier period, equally devoid of historic foundation; and this supposed early Christian Church has given rise to what may be called the Culdean controversy, by which the true history has been further obscured. It is a disadvantage which affects the history of all churches, that it is almost inevitably viewed through the medium of the ecclesiastical prepossessions of the historian. This has been peculiarly the case with the history of the early church in Scotland, which has become the battle-field on which Catholic and Protestant, Episcopalian and Presbyterian, have contended for their respective tenets; and this evil is greatly aggravated when the basis of the controversy consists of such a strange mixture of fact and fable as that which characterises the history of the early Scottish Church, as it is usually represented. People are tired, however, of this incessant repetition by church historians of the same one-sided arguments, and partial statement of authorities adduced to assimilate the early Celtic Church, in its doctrine and constitution, to one or other of the great ecclesiastical parties of the modern church. They want to know what sort of a church this early Celtic Church really was, irrespective of all ecclesiastical bias, and this the Author has attempted to show in the following volume. He has endeavoured simply to tell the tale of the early Celtic Church, as he finds it recorded in the oldest and most authentic sources of information. With this view he has treated of the history of the church mainly in its external aspect, and has been unable to touch, to any great extent, upon its doctrinal history, or to attempt to exhibit its theological characteristics. The discussion of these questions must still be left to the polemical historians. From the works of these writers the Author has thus derived little assistance; but his task has been greatly aided by another class of writers, who have brought to bear upon the different branches of the subject that sound judgment, extensive research, and critical acumen, which are requisite to extricate the true history of the early church from the fictitious and controversial matter with which it has been encumbered.