Arrangement
The cards are grouped in series according to the publisher. Within each series, items are first arranged numerically according to the number indicated on the card. Those without numbers are placed at the end of each series in alphabetic order.
Administrative/Biographical History
The set of stereograph cards are part of the Colorado-Henkle Collection, which consists of material, mostly published, relating to the state and territory of Colorado. The date of donation is unknown, but purchase notes on the backs of stereograph cards indicate they were donated to NIU sometime in the 1970s. The core of the Colorado-Henkle Collection (671 items) was purchased from ABAA seller Kenneth Nebenzahl in July 1969. The collection saw substantial grown between 1969 and 1978 as Herman Henkle regularly donated items to the collection before his death.
