Crystal Singer series

The Crystal Singer series is a series of science fiction novels written by Anne McCaffrey.

The series is set on the planet Ballybran which is under a permanent biohazard travel restriction. Ballybran is home to one of the FSP's wealthiest, yet most reclusive organizations — the Heptite Guild. Source of invaluable crystals vital to various industries, the Heptite Guild is known to require absolute, perfect pitch in hearing and voice for all applicants, especially those seeking to mine crystal by song.

Novels in the series are:

• Crystal Singer (1982) ISBN 0-345-32786-1 (first published in four parts in Continuum 1, 2, 3, & 4, edited by Roger Elwood)
• Killashandra (1986) ISBN 0-345-31600-2 (includes a Brainship from the Ship series above, in a minor role. This was not a main character in any novel.)
• Crystal Line (1992) ISBN 0-345-38491-1 (includes a Brainship from the Ship series above, although not a main character in any novel, and, furthermore, is not the same Brainship from 'Killashandra')