In the religious history of almost every age and country, we meet with a certain class of minds, impatient of mere ceremonial forms and technical distinctions, who have pleaded the cause of the heart against prescription, and yielded themselves to the most vehement impulses of the soul, in its longing to escape from the sign to the thing signified—from the human to the divine. The story of such an ambition, with its disasters and its glories, will not be deemed, by any thoughtful mind, less worthy of record than the career of a conqueror. Through all the changes of doctrine and the long conflict of creeds, it is interesting to trace the unconscious unity of mystical temperaments in every communion. It can scarcely be without some profit that we essay to gather together and arrange this company of ardent natures; to account for their harmony and their differences, to ascertain the extent of their influence for good and evil, to point out their errors, and to estimate even dreams impossible to cold or meaner spirits. These Mystics have been men of like passions and in like perplexities with many of ourselves. Within them and without them were temptations, mysteries, aspirations like our own. A change of names, or an interval of time, does not free us from liability to mistakes in their direction, or to worse, it may be, in a direction opposite. To distinguish between the genuine and the spurious in their opinion or their life, is to erect a guide-post on the very road we have ourselves to tread. It is no idle or pedantic curiosity which would try these spirits by their fruits, and see what mischief and what blessing grew out of their misconceptions and their truth. We learn a lesson for ourselves, as we mark how some of these Mystics found God within them after vainly seeking Him without—hearkened happily to that witness for Him which speaks in our conscience, affections, and desires; and, recognising love by love, finally rejoiced in a faith which was rather the life of their heart than the conclusion of their logic. We learn a lesson for ourselves, as we see one class among them forsaking common duties for the feverish exaltation of a romantic saintship, and another persisting in their conceited rejection of the light without, till they have turned into darkness their light within. But the interest attaching to Mysticism is by no means merely historic. It is active under various forms in our own time. It will certainly play its part in the future. The earlier portion of this work is occupied, it must be confessed, with modes of thought and life extremely remote from anything with which we are now familiar. But only by such inquiry into those bygone speculations could the character and influence of Christian Mysticism be duly estimated, or even accounted for. Those preliminaries once past, the reader will find himself in contact with opinions and events less removed from present experience.