In November 2011, Caro estimated that the fifth and final volume—expected to treat the remainder of Johnson's presidency and his life thereafter In March 2013, he affirmed a commitment to completing the series with a fifth volume. As of April 2014, he was continuing to research the book. In a televised interview with C-SPAN in May 2017, Caro confirmed over 400 typed pages as being complete, covering the period 1964–65; and that once he completes the section on Johnson's 1965 and 1966 legislative achievements, he intends to move to
Vietnam to continue the writing process. In an interview with the
New York Review of Books in January 2018, Caro said that he was writing about 1965 and 1966 and a non-chronological section about the relationship between Johnson and Bobby Kennedy. Asked if he still planned to visit Vietnam soon, Caro replied: "Not yet, no. This is a very long book. And there's a lot to do before that's necessary. I'm getting close to it now." In December 2018, it was reported that Caro is still "several years from finishing" the volume. In January 2020, Caro said he had "typed 604 manuscript pages so far" and is "currently on a section relating to the creation of Medicare in 1965". He also revealed in separate interviews that he had completed sections related to Medicare and was receiving digital versions of Vietnam-era documents from the
Johnson Presidential Library. Caro provided a few more updates in a February 2025 interview with
Smithsonian magazine, where he revealed that he had written 980 pages for his manuscript. He also revealed that he was still working on sections for the creation of
Medicare and
Medicaid, from its management from Senator
Russell Long to its passage through the Senate, and that he planned on embarking his trip to
Vietnam once he finished those sections. He also clarified that while he will not allow someone else to finish his work, he will release whatever he has completed to the public if he dies. ==Themes==