The collection carried out archaeographic publication of documents of the XVI - the first half of the XVII century, which came out of the pen of Ukrainian Cossacks (foremen and ordinary Cossacks) or were addressed to the Zaporizhzhya Army as a whole or to its various representatives. The source base of the collection covers letters, universals, glates, instructions, agreements, oaths. The annexes contain Sejm constitutions on the Cossack issue, confessions of Cossacks, instructions to envoys to the Zaporizhzhya Troops. For scientists, students and everyone who is interested in the history of the Ukrainian Cossacks and Ukraine as a whole.