1) Carry Ons: Travelling Chihuahuas (2004) by Sharon Montrose.
2) Chihuahua Champions 1984-2004 (2008) by Shae Pata, one of two volumes documenting show winners.
3) Chihuahua Savvy (2006) by Barbara Scott.
4) From Peril to Princess: The Chronicles of Shelby (2007) by Leslee B. Waite, children's book about a chihuahua that started life discarded in a dumpster, but grows up to make friends all across America. It was written shortly after the death of the author's beloved Shelby, as a celebration of the dog's grand life. It took her five months to complete the book, during which "slowly my grief was replaced with incredible joy of seeing Shelby come 'alive' again."