There was recently an enquiry about books on Sansevierias.
The most recent one that I know of is: The Sansevieria Book, by Hermine
Stover. This is available from: Endangered Species, P.O. Box 1830,
Tustin, California 92680, U.S.A. It is quite a good book about this very
wonderful group of plants.
I understand that a tradition has developed of giving a gardener a
Sansevieria on his 40th birthday as a gesture of good will and
demonstration of a wish for long life . . .
There is really nothing to compare to the sight of one of the variegated
Sansevierias back-lit in a window, veritably glowing! Sansevierias are
truly elite and worthwhile plants.