These two words, sometimes used in combination, are often misused in technical writing. "Former" refers back to the first of two things mentioned; "latter" refers back to the second of two things mentioned:
The chief spices used in this dish are coriander and cumin, the former being less pungent.
The two diseases studied were Hodgkin’s disease and leukemia, with the latter resulting in more fatalities this year.
Last year’s tornadoes in Tracy, Minnesota, and Kansas City, Kansas—the former measuring F4 and the latter F5—were the two most destructive tornadoes of the summer.
When more than two members of a list are involved, or when the sentence’s context does not clearly indicate an antecedent (a word or phrase being referred back to), then strictly avoid using "former" and "latter."