A grasp of chronology, simple as it may seem, is a fundamental skill of any historian. By "chronology," we mean what happened, in which order.
Chronology is important because the exact order in which events occur helps us understand the cause and the effect of those events, and thereby allow us to step back and view the "big picture" of history - how and why events unfold in the way they do, and how they are related.
In order to establish the exact order in which events unfold, consider preparing detailed timelines of the period you are studying. Such timelines will ensure that you always maintain an overview of the sequence of events at stake, and that you do not confuse cause and effect.
In the section on narrative history we provide a timeline of Hitler's foreign policy prior to World War II; in this section, we offer another timeline, below, on U.S.-Japanese relations prior to the United States' entry into the war. Based on the exact sequence of events, we will draw your attention to some interesting aspects of America's entry into the war, which those without a firm grasp of the chronology risk missing.
The following timeline is based on the information provided in the World War II-chapter of a standard college-level textbook of American history:
James L. Roark, et al. The American Promise: A History of the United States, v. 2: From 1865, 3rd edition. New York: Bedford St. Martin's, 2005. 916-918:
Significant moments in the evolution of U.S.-Japanese Relations prior to Pearl Harbor:
The events listed above are all well-established, but are usually presented non-chronologically. In a series of paragraphs devoted to the deteriorating American-Japanese relations, textbooks generally mention, in no particular order, that the U.S. had broken Japan's codes, that FDR imposed a trade embargo on Japan, that the U.S. intercepted Japanese messages warning of an attack on U.S. Pacific bases, that FDR ordered aircraft carriers removed from Pearl Harbor, that Japan attacked Pearl Harbor, and that FDR, declaring December 7 "a date which will live in infamy," was finally able to rally the previously isolationist nation to action after Japan's "surprise attack." (This, incidentally, is the way Roark's American Promise presents the information, on pp. 916 918, although not quite this chronologically.)
Notice how the exact order of events, as listed above, raises interesting questions. Just how much of a "surprise attack" was Pearl Harbor, do you think? What factors in the timeline above suggest that the U.S. might have had prior knowledge? Why would the U.S. have allowed the attack to occur, if (as some argue) it knew the attack was imminent? Why not attack Japan preemptively? Why remove American aircraft carriers from Pearl Harbor prior to the attack? What significance do you ascribe to FDR's purported comment to Churchill that he would seek out "some incident that might trigger public support for full-scale American entry into the war against Germany" (916)? How did the Japanese attack on Pearl Harbor contribute to this effort?
It remains unknown whether or not FDR knew about the impending attack, and whether he might even have deliberately provoked it, beginning with the trade embargo. Nevertheless, historians have been mulling over issues such as those listed above for decades. Once you have the exact chronology of events down, you too can begin asking questions and proposing answers on this, and any interesting topic in history.