As the first commercially-successful multi-tool, the PST is legendary. All of the early versions are popular as collectibles.
Tim Leatherman prototyped the PST in the mid 1970s, and filed a patent application in July 1978 for a folding, full-sized set of pliers that had a blade and additional tools built into the handles (granted in December 1980). He offered the design to a few larger US tool and knife manufacturers. When they all rejected the idea, he started his own small manufacturing plant, and began to sell the first PSTs in May 1983. They quickly became popular.
The earliest Leatherman PSTs are stamped US PAT 4238862 and LEATHERMAN TOOL on one arm, and POCKET SURVIVAL TOOL on the other. They have a rather primitive drop point blade, pliers with a square profile near the pivot, an awl with ragged mill marks, and a can opener bevel that faces out. Early PSTs lack the small lanyard ring that is included on every later version.
There are two variants to the original Pocket Survival Tool. The earliest ones were held together by four rivets. However, the blade and tools tended to loosen and flop around, so the rivets were soon replaced with four sets of knurled screws, similar to later models. They allow the tool to be disassembled and repaired, but can only be opened with a special wrench.
After a couple years, the first PST was replaced by a succession of undated “small letter” PST tools without the "Pocket Survival Tool" stamp, and by “big letter” versions with some parts manufactured in Japan. There is some overlap of tools and handle labeling among the three different types of early PST, so it is probable that they all were sold simultaneously for a couple of years, as the Leatherman Tool Group struggled to keep up with demand. Tool dating is uncertain up until 1992, when each tool started to be dated inside the handles.