Children of the Lens by E.E. Smith

To you who have scanned this report, further greetings:

Since I, who compiled it, am only a youth, a Guardian only by title, and hence unable to visualize even approximately either the time of nor the necessity for the opening of this flask of force, I have no idea as to the bodily shape or the mental attainments of you, the entity to whom it has now been made available.