Follicular unit transplantation is a method of hair restoration surgery whe
re hair is transplanted exclusively in its naturally occurring, individual
follicular units. The evolution and rational for follicular unit transplant
ation will be discussed, as well as the logic for the various techniques us
ed in its implementation. Specifically, the logic for single strip harvesti
ng, stereo-microscopic dissection, automated graft insertion, and large tra
nsplant sessions will be reviewed. The central role of the follicular unit
constant in the surgical planning will also be discussed.