23 year-old left-back Tom Williams has today joined the Reds from Birmingham City where he had two years remaining on his Birmingham contract.
Williams told the official Barnsley FC website: "Two things have attracted me to Barnsley. The size of the club and Paul Hart.
"I really believe this club is going places. I've looked at the facilities and can see that Barnsley has been a Premier League set-up not too long ago.
"There is no doubt that Barnsley can challenge for promotion next season. In Peter Ridsdale they have a chairman who believes in his manager and a manager who has told me clearly how wants his team to play and his views on the future.
"I want to improve as a player and I still want to be coached. I've spoken to people in football who tell me Paul Hart is the man to do that."
Reds manager Paul Hart said: "Tom is very quick and agressive. He will be a real plus for the team we are building here.
"We identified him as a key signing several weeks ago because there is such a shortage of naturally left-sided players in the game. I'm delighted to have Tom on board alongside the emerging talent of Robbie Williams."
Hart added: "There is a big turn-around here and I hope we have the players in place for when we return to training on June 28th."