It's not expensive, either. To buy a copy, go to the NMGS Press webpage at this link and order book E-5. The book is only $7.50 for NMGS members, $15.00 for non-members. If you have the 1st or 2nd edition of the book, you find that the 3rd edition is even more comprehensive that its predecessors.
Many records can be found at the Socorro County Courthouse:
PO Box 1, Socorro, NM 87801-0327]
Ph: 505-835-0589; Fax 505-835-4629
There are also finding aids online that can be used to find records that are not at the courthouse. These may be found at the Online Archive of New Mexico. Two collections are at the New Mexico State Records Center and Archives, Santa Fe. These are:
* Records of the United States Territorial and New Mexico District courts for Socorro County, 1851-1933. MS 1976-031. Click this link to access the finding aid.
* Socorro County, N.M. Records, 1851-1935. MS 1974-029. Click this link to access the finding aid.
Socorro was created in 1852 as an original New Mexico county. All of Catron (est.1921) and Sierra (est.1884) Counties, and parts of Lincoln (est. 1869)and Torrance (est.1903) Counties were once part of Socorro County. Therefore, some records for these other counties may be found in the Socorro County archives.
Source: Daniel, Karen Stein, CGsm, Genealogical Resources in New Mexico: Third Edition (Albuquerque: New Mexico Genealogical Society, 2007), pp. 18-23.