Title:  Oracle9i RMAN Backup & Recovery
ISBN:   0072226625
Author: Robert Freeman & Matthew Hart

Chapter 2:
Page 43
Description of parameter CONTROLFILE_RECORD_KEEP_TIME 
incorrectly states if set to 0 means that the records 
are never reused. The control file will grow and grow 
and become unmanageable.

The correct information is as follows:
CONTROL_FILE_RECORD_KEEP_TIME specifies the minimum 
number of days before a reusable record in the control 
file can be reused. In the event a new record needs to 
be added to a reusable section and the oldest record 
has not aged enough, the record section expands. If 
this parameter is set to 0, then reusable sections 
never expand, and records are reused as needed.