This book records transactions where the U.S. Government (agents) was the Grantor. Some early settlers walked into the Land Office and made a purchase. For others, they were given a tract of land in payment for their service in the United States Armed Forces.
These Land Grants transactions are indexed by location ie. Range and Township.
These records may be found on-line by going to The Bureau of Land Management (BLM). They may be downloaded and printed.
https://glorecords.blm.gov/search/default.aspx