J. Michael Lennon is an American academic and writer who is the Emeritus Professor of English at Wilkes University and the late Norman Mailer’s archivist and authorized biographer.

[2][4] While working on his dissertation in 1971, Lennon watched Gore Vidal and Mailer's altercation on The Dick Cavett Show.

[10] Mailer would later add: "Sometimes I think Mike Lennon and I were as designed for each other as some species of American Yin and Yang, as hot dogs, perhaps, and mustard.

At Lennon's suggestion, in 1994 the Mailer papers, previously housed in Manhattan, were moved to a large professional storage facility in Pennsylvania.

This arrangement made it more convenient for Lennon and Mailer's current biographer and archivist Robert F. Lucid to have access.

Lennon and his wife moved full-time to their condo in Provincetown where Mailer had begun writing his final novel, The Castle in the Forest (2007), in fall of 2000.

[17] Lennon had kept extended notes on Mailer's table talk, and also interviewed him on many aspects of his public and private life.

Over the next four years Lennon interviewed 86 people, including his ex-wives, children, cousins, sister, nephew, and many close personal and literary friends, including Don DeLillo, Gay Talese, Robert Silvers, Barbara Probst Solomon, David Ebershoff, Ivan Fisher, Eileen Fredrikson, Lois Wilson, Carol Holmes, Tina Brown, Harry Evans, James Toback, Nan Talese, Dotson Rader, Doris and Dick Goodwin, William Kennedy, Richard Stratton, Mickey Knox, and Lawrence Schiller, Mailer's most important collaborator.

The Lennons made several month-long visits to the Mailer archives in Texas, in 2008 and 2009, and in the fall of 2009, he began writing, breaking his daily routine only to conduct interviews.

He continued to teach and assisted University of Pennsylvania professor, Robert F. Lucid, then Mailer's authorized biographer and archivist.

He served from 2005-2007 as a literary consultant at the Harry Ransom Center, University of Texas at Austin, where he assisted in the cataloging of Mailer's papers, and was a Fellow there in 2009.

[2] Lennon chose the title Double Life because he saw that Mailer had two minds about most anything of consequence, reflecting his belief that everyone's psyche has two separate personalities.

[4] An aspect of Mailer's double life also includes his being born between two generations: one as part of the post-World War II writers like James Jones and the other as participant of the sixties' New Journalism.

[27] "Mailer knew me as an archivist and a bibliographer and a fact fetishist who collected the bits of his life and work", Lennon says; "I really tried to bring in material that no one had ever seen before, and God knows I had plenty of it".

[31] French calls it "a riveting blow-by-blow account of a vigorous life",[32] and Elliott avers that Lennon "does an admirable job of allowing Mailer's various iterations of himself to emerge without judgment or apology".

[33] Elliott calls Double Life an "excellent academic resource with over 100 pages of endnotes—a treasure for literary scholars" that is "enlightening, lively, and a pleasure to read, it is almost certain to become the standard Mailer biography".

"[2] Moore adds that the biography is a "behemoth of appropriate scope to frame a man who led a big life,"[4] and Pritchard writes that DL "won't be improved upon" as it "is a feat [Lennon] performs with care and without pomposity.

"[34] Margulies writes of A Double Life: "Lennon manages to resist inserting a personal agenda into the biography and, as such, it reads as a rare and true portrait of the writer, who insisted that his biographer 'put everything in'".

[36] It includes letters to celebrities like James Baldwin, Saul Bellow, Jorge Luis Borges, Fidel Castro, Martin Luther King Jr., Kate Millett, and Hillary Rodham Clinton, and also personal missives to fans, critics, editors, friends, family and ordinary people.

Dwight Gardner calls it a collection of "mostly minor gleanings from a major writer" that, however, has "umpteen pleasures to pluck out and roll between your teeth, like seeds from a pomegranate".

[3] John R. Coyne opines that Selected Letters is a "well-written and thoughtful study so comprehensive that it seemed to obviate the need for any further biographical data,"[38] and Ronald Fried states that his letters shows Mailer's almost innocent notion that he could make the world better and they emerge "as essential to the work that would become his indelible contribution to America literature.