All of the series listed below are open-ended, that is to say we try to add at least one title a year to the series with no particular number of volumes in the series stated. Listed below are the names of the series with the number of volumes in print so noted.

BATTLE OF THE LITTLE BIG HORN SERIES (5 VOLUMES)
CUSTER TRAILS SERIES (9 VOLUMES)
ECHOES OF THE LITTLE BIG HORN SERIES (5 VOLUMES)
JIMMY BOOK SERIES (1 VOLUME)
MONTANA AND THE WEST SERIES (15 VOLUMES)
NATIVE AMERICAN INDIAN LEADERS SERIES (1 VOLUME)