The reception Clinton gets is likely to help her decide whether to launch a bid to be elected the first woman U.S. president. Polls show she is the overwhelming favorite for the Democratic presidential nomination should she run.
Clinton says she will make up her mind about a presidential run after the November congressional elections, though many Democrats think she will run. Those close to her say the book tour will help her decide.
"I think essentially this is to gauge what the reaction is to the book and gauge what the reaction is as she tours the country," said a Clinton associate.
The tour allows her to "get her toe in the water without drowning," the associate said.
Clinton - a woman whose every move, from her hairstyle to her pending status as a grandmother, is watched with an unsparing eye - will use the book tour to shift the conversation to her foreign policy record.
The book, titled "Hard Choices," hits bookstores on Tuesday.
The tour, with stops in New York, Chicago, Philadelphia and Washington this week, puts her in the public spotlight in a more intensive way than at any time since she resigned as secretary of state early in 2013.
Clinton loyalists believe the book will show her to be a foreign policy pragmatist during what she considers to be the most successful period of her political life.
Her four years at the State Department were not, however, without controversy, and Clinton is using the tour to defend her record and explain her reasoning behind key decisions.
A chapter is devoted to the Sept. 11, 2012, attack by militants on a U.S. facility in Benghazi, Libya, in which the U.S. ambassador to Libya was killed. Republicans have accused then-Secretary Clinton of not doing more to ensure the safety of Americans there.
In an ABC interview airing on Monday night, Clinton said she was "ultimately responsible for my people's safety." But pressed on whether there was more she could have done, Clinton said there were limits.
"I'm not equipped to sit and look at blueprints, to determine where the blast walls need to be or where the reinforcements need to be," she said. "That's why we hire people who have that expertise."
Republicans are vowing to keep the issue alive, saying it calls into question how she would deal with foreign policy crises as president.
"Benghazi is not going away," said Republican strategist Scott Reed.
In the book, Clinton treads a careful path between being a faithful servant to Obama and someone who would chart her own course on the global stage.
In what may be an attempt to head off criticism from the left, she disavows her 2002 Senate vote in favor of the Iraq war, a vote Obama used effectively against Clinton in defeating her for the nomination in 2008.
She defends her much-criticized "reset" in U.S.-Russian relations as a linguistic mistake, an episode that is all the more glaring now with Russia's incursion into Ukraine and Washington-Moscow ties at their lowest ebb since the Cold War.
Clinton says she differed with Obama on deciding not to arm Syrian rebels. She is skeptical about negotiations with the Taliban, a move that gives her some distance from uncomfortable questions regarding Obama's swap of five high-value Taliban prisoners for Army Sgt. Bowe Bergdahl.
"It's a campaign book, but what she is trying to do is set the record straight, then move on to other things. So that's why it's coming out now," said Keith Urbahn, a book agent for conservatives.
The book tour recalls Clinton's "listening tour" of New York state, which she conducted before deciding to run for a New York Senate seat in 2000, an election she won.
"I am convinced that she has already decided to run and that she will run and that she will be the nominee. I think this is just the first phase of the process," said Democratic strategist Bob Shrum, who advised John Kerry on his 2004 presidential run.