First things first...

First let's define genealogy as the study of the descent of a person, family, or group from an ancestor or other older forms. Now let's define family history as the study of the history of a person, family, or group. Similar? You bet.

Where do you begin...

Where do you begin on your genealogy? Listen to your teacher, before becoming a professional genealogist i'd invested thousands of hours teaching others and volunteering to help advanced researchers. You begin with yourself by documenting when you were born, where it was, and who your parents were. Sounds easy but i've run into several cases where i've asked new researchers to document their parentage and they find out they were adopted and it had been kept a secret by their usually now deceased adoptive parents... so genealogy without documentation is a fantasy that might be true.

Next accumulate information on your immediate family before proceeding to your grandparents... much has been written on this elsewhere.

Those three letters are an acronym for the French carte de visite or visiting card. This style of antique photography took over in popularity from the daguerreotype or ambrotype of the 1840s and 1850s. Though they provided lovely images, the dag and ambro were easily damaged and not suitable to tuck into an album or a letter to a friend.

The Civil War era of the 1860s, however, saw a wide acceptance of the cdv, the invention of either Adolph Disderi in 1854 or Louis Dodero in 1851.

The cdv photograph belongs to the group known as card photographs because the albumen print (a mixture of egg whites, sodium chloride, and silver nitrate) was mounted on paper cards. 

The size of a cdv is 2 1/4" x 4 1/4" (although you nay see them sized as 4" x 2 1/2")

The photographer might print, stamp, or emboss his name and town or state on the back (backmark) of the card, below the image, or may omit identification altogether. 

The Civil War soldier loved the cdv. These young men would often pose in studios many miles from their home, and obtain images to tuck in with a letter to the folks they left behind, or a sweetheart.

Cdv photos were cheaper and easier to produce, and required less skill on the part of the photographer. Thus, more of the public, unable to afford the dag or ambro, could afford the cdv image.