Reference to the astral plane, or Kâmaloka as it is called in Sanskrit, has frequently been made by Theosophical writers, and a good deal of information on the subject of this realm of nature is to be found scattered here and there in our books; but there is not, so far as I am aware, any single volume to which one can turn for a complete summary of the facts at present known to us about this interesting region. The object of this manual is to collect and make some attempt to arrange this scattered information, and also to supplement it slightly in cases where new facts have come to our knowledge. It must be understood that any such additions are only the result of the investigations of a few explorers, and must not, therefore, be taken as in any way authoritative, but are given simply for what they are worth. On the other hand every precaution in our power has been taken to ensure accuracy, no fact, old or new, being admitted to this manual unless it has been confirmed by the testimony of at least two independent trained investigators among ourselves, and has also been passed as correct by older students whose knowledge on these points is necessarily much greater than ours. It is hoped, therefore, that this account of the astral plane, though it cannot be considered as quite complete, may yet be found reliable as far as it goes.