President-elect Donald Trump is about ready to receive briefings on what President Barack Obama calls "our deep secrets," including critical information on top-secret operations, intelligence operations, and the "Black Book" of contingency plans on the use of nuclear weapons.

Most presidents-elect have received the briefings during the transition period between the general election and the inauguration, reports The Washington Post.

Trump, as a presidential nominee, has received some intelligence briefings, but there is a series of other briefs for a president-elect, although his spokeswoman, Hope Hicks, said she could not provide a schedule for when he'll receive them.

Obama, after receiving one of the briefings in 2008, said that the matter was sobering, telling an adviser he was "inheriting a world that could blow up any minute in half a dozen ways, and I will have some powerful but limited and perhaps even dubious tools to keep it from happening.”

The first briefing will give information on Special Access Programs for intelligence operations, and could include, if Trump wants, names of dozens of CIA operatives overseas. Usually, presidents do not seek those names, unless the asset is particularly important, reports The Post.

Trump will also learn the intelligence community considers the president the "First Customer," as it responds to all presidential requests.

A second briefing will involve covert actions, or "Findings," that include intelligence orders signed by the president, some of which include broad authority for lethal counterterrorism activities.

Obama's orders for covert actions will continue unless Trump changes them once he takes office. Usually, the president-elect reviews covert actions before taking office, and Trump could add more operations after he is sworn in.

Trump will also be given information on domestic counterrorism operations, and about the "continuity of government," or the rules designed for implementing presidential succession in the event in which he'd die or could not carry out his presidential duties.

The third briefing includes information on nuclear-war options and plans, including about the "football," the briefcase carrying the nuclear authentication launch codes. The briefcase, carried by the military aide to the president, also contains the "Black Book," officially named the "Presidential Decision Handbook," containing top-secret plans for the use of nuclear weapons, and estimates on casualty numbers.