The Seven books, Samuel Pufendorf 's monumental work on the reign of Charles Gustav and Second Northern War, printed in 1696, still retains its value. It is not just about the participation of Pufendorf in the events he later described, or that he knew many outstanding commanders and high-ranking dignitaries of the epoch. For obvious reasons no historian will ever acquire such intimate knowledge of the said matters. The great strength of the book lies also in the synthetic evaluation of all the important theatres of war, either military or diplomatic. In this great, Pan-European conflict, Sweden was at the centre of the struggle, which naturally presents us with a broad perspective. Therefore, not only does De rebus retain the information concerning the course of events in Stockholm, London, Warsaw or Copenhagen, but also descriptions of the developments in Ghana or Constantinople. Ergo the book still remains an important reference.

Undeniably, we have a large number of more detailed and modern studies at our disposal. Most often, however, they will cover only a single event. Assembling all these fragments together would certainly give a great result, but overcoming language difficulties and combining diverse, national and historiographical traditions is a somewhat difficult, if not an unfeasible task – although it must be stressed that especially in the field of military and history of diplomacy we have some interesting proposals, to name the works of Peter Englund, Yaroslaw Fedoruk, Robert I. Frost, Mirosław Nagielski or Henadz Sahanovich (alphabetical order).

Yet the work of Pufendorf cannot be accepted easily and without reservation, as it still hides a lot of mysteries and is not devoid of flaws. This is primarily due to the author's process of writing, his specific use of historical sources. Sometimes he exploited unique documents from the archives, but at times he was content with mere copying of some printed texts into his book. Certainly he worked quickly, which does not allow absolute concentration on each sentence. It is not always easy to check his sources, as some documents perished or certain facts are inconsistent with other accounts. However, when comparing Pufendorf 's stories with the results of the most recent research, we also perceive that his old text still retains its validity, and what is more, it can add some new elements to our perception of the epoch.