It has been suggested that Russell and or Wittgenstein arrived at a truth-table device in or around 1912 [Shosky 1997], and that, since the history of its development is so complex, the best one can claim is that theirs may be the first identifiably ascribable example. However, Charles Peirce had, unbeknownst to most logicians of the time, already developed a truth table for binary connectives of his algebra of logic in 1902.
"The Genesis of the Truth-Table Device,"
Russell: the Journal of Bertrand Russell Studies:
1, Article 5.
Available at: http://digitalcommons.mcmaster.ca/russelljournal/vol24/iss1/5