The original Thinline arrived on the scene in 1968 and was revamped in 1972 with the introduction of the 2nd generation model (Thinline II). Several theories exist for the Thinline's creation- two of which are to create a lighter working guitar for players, or combat the diminishing supply of "light-grade" ash wood available at the time.
Therefore it's a semi-hollow body guitar. Literally it's a partially hollowed-out Tele Standard. The Thinline shed approximately a pound of weight compared to the solid-body Tele.
1968 Thinline Telecaster (below)
Roger Rossmeisl, formerly of Rickenbacker and their “main-brain” behind the semi-hollow 300 series Rickenbackers, helped lead the design of the Thinline.
In 1972 it got more interesting.
Before 1972 Thinlines featured standard Telecaster single-coil pickups, but this year Fender introduced the "Wide Range Humbucker" pickups designed by Seth Lover, formerly of Gibson.
Seth invented the humbucker pickup for Gibson around 1955 and they were introduced on Les Paul models in 1957.
Humbucker’s get their name because they “buck the hum”. Having two wound coils rather than one (single coil) the interference is canceled out making for a thicker or warmer tone when compared to a single coil.
Production of the first run of Thinline’s ended in 1979.
1972 Thinline Telecaster (below)
Smaller details originating from 72-
Three-bolt neck attachment
Redesigned pickguard to surround the pickups
Headstock was stamped "Telecaster Thinline"
Specs-
Body: Semi-hollow Ash
Pickups: 2 Fender Wide Range Humbuckers
Tuners: "F" style
Maple Neck with skunk stripe