There was indubitably a period in the past--in the infancy of the human race--when it was much more largely assisted from outside than is at present the case. At the time when all its Buddhas and Manus, and even its more ordinary leaders and teachers, were drawn either from the ranks of the deva evolution or from the perfected humanity of a more advanced planet, any such assistance as we are considering in this treatise must also have been given by these exalted beings. But as man progresses he becomes himself qualified to act as a helper, first on the physical plane and then on higher levels; and we have now reached a stage at which humanity ought to be able to provide, and to some slight extent does provide, invisible helpers for itself, thus setting free for still more useful and elevated work those beings who are capable of it. It becomes obvious then that such assistance as that to which we are here referring may most fitly be given by men and women at a particular stage of their evolution; not by the adepts, since they are capable of doing far grander and more widely useful work, and not by the ordinary person of no special spiritual development, for he would be unable to be of any use. Just as these considerations would lead us to expect, we find that this work of helping on the astral and lower mental planes is chiefly in the hands of the pupils of the Masters--men who, though yet far from the attainment of adeptship, have evolved themselves to the extent of being able to function consciously upon the planes in question. Some of these have taken the further step of completing the links between the physical consciousness and that of the higher levels, and they therefore have the undoubted advantage of recollecting in waking life what they have done and what they have learnt in those other worlds; but there are many others who, though as yet unable to carry their consciousness through unbroken, are nevertheless by no means wasting the hours when they think they are asleep, but spending them in noble and unselfish labour for their fellow-men. What this labour is we will proceed to consider, but before we enter upon that part of the subject we will first refer to an objection which is very frequently brought forward with regard to such work, and we will also dispose of the comparatively rare cases in which the agents are either nature-spirits or men who have cast off the physical body.