
Louis Eliasberg (1896-1976) was a Baltimore financier who avidly collected coins from 1925 until 1976. His goal was to assemble a complete collection of United States regular-issue coins. He accomplished this monumental feat by 1950, by purchasing the last gold coin he needed (1841 $2 1/2) in 1949 and the last silver coin he needed (1873-CC No Arrows dime) in 1950. From 1950 until his death in 1976, he concentrated on keeping his collection current, adding a few better-condition pieces, and sharing his collection with the numismatic community through various exhibitions. He was even featured in an article in LIFE magazine.
Louis Eliasberg accomplished what no one else accomplished before or since. He built a collection of regular-issue United States coins comprising all then-known dates and mintmarks. He is the only person to ever build a complete set of U.S. coins. He avidly sought every single coin he needed to accomplish his goal, in the process purchasing coins from most of the major dealers of his day.
Eliasberg's largest and most important purchase occurred in 1942 when he purchased the Clapp Estate Collection through Stack's for $100,000. The Clapp Collection had been built first by J.M. Clapp from the 1880s through his death in 1906, and then his son John H. Clapp from 1906 on. The Clapp Collection was not only nearly complete, it contained coins of extraordinary quality, including spectacular-quality coins that J.M. Clapp had acquired directly from each of the Mints in the year of issue from 1892 to 1906. Louis Eliasberg added the Clapp Collection to his, then expanded it and added the great ultra-rarities.

The Eliasberg gold coins were auctioned by Bowers and Ruddy in 1982. The Eliasberg Copper, Nickel and Silver coins were auctioned by Bowers and Merena in two sales in 1996 and 1997. The three Eliasberg sales are among the greatest in numismatic history.
Note that prior to the 1980s, most collectors mixed proofs and circulation strikes. So the Eliasberg collection features circulation strikes for the branch mints and proofs for most of the Philadelphia Mint issues. This was how collectors built sets at the time and a collection was considered "complete" if it had one example from each date and mint, regardless of whether the examples were circulation strikes or proofs. But for his time, Louis Eliasberg truly accomplished "The Impossible Dream"... he built a complete set of United States coins.
PCGS is now in the process of adding the Eliasberg coins to the PCGS Set RegistrySM so collectors can compare their collections to this all-time great collection. The first sets added are the Eliasberg gold dollars. Use this link to view the Eliasberg gold dollars.