Holzer has authored, co-authored, and edited 30 books: The Lincoln Image (1984); Changing the Lincoln Image (1985); and The Confederate Image, (1987), all with Mark E. Neely, Jr. and Gabor S. Boritt; The Lincoln Family Album (1990), Mine Eyes Have Seen the Glory: The Civil War in Art (1993), and The Union Image (2000) with Neely; and Lincoln on Democracy (1990) with Mario M. Cuomo. He has also published The Lincoln-Douglas Debates (1993); Washington and Lincoln Portrayed (1993); Dear Mr. Lincoln: Letters to the President (1993); Witness to War (1996); The Civil War Era (1996); The Lincoln Mailbag: America Writes to the President (1998); The Union Preserved (with Daniel Lorello, 1999), The Lincoln Forum: Abraham Lincoln, Gettysburg, and the Civil War (co-edited with John Y. Simon and William Pederson, 1999); Lincoln as I Knew Him (1999); Lincoln Seen and Heard (2000); Abraham Lincoln, The Writer (2000, named to the Children's Literature Choice List, and the Bank Street "Best Children's Books of the Year"); Prang's Civil War: The Complete Battle Chromos of Louis Prang (2001), State of the Union: New York and the Civil War (2002); The Lincoln Forum: Rediscovering Abraham Lincoln (co-edited with John Y. Simon, 2002); and The President is Shot! The Assassination of Abraham Lincoln (2004). His book Lincoln At Cooper Union: The Speech That Made Abraham Lincoln President (2004), won a 2005 Lincoln Prize, the most prestigious award in the field.

Holzer's Latest books are Lincoln in the Times: The Life of Abraham Lincoln as Originally Reported in the New York Times, co-edited with David Herbert Donald (St. Martin's Press, 2005), which presents for the first time in a single volume the original press coverage Lincoln elicited in the country's newspaper of record, with expert introductions and commentary by Holzer and Donald; The Battle of Hampton Roads: New Perspectives on the U.S.S. Monitor and C.S.S. Virginia (co-edited with Tim Mulligan); The Emancipation Proclamation: Three Views (co-authored with Edna Greene Medford and Frank J. Williams); a new and enlarged edition of The Lincoln Family Album, co-authored with Mark E. Neely, Jr.; Lincoln in the Collections of the Indiana Historical Society; Lincoln Revisited (2007), a new volume of Lincoln Forum essays co-edited with John Y. Simon and Dawn Vogel; Lincoln's White House Secretary: The Adventurous Life of William O.Stoddard (2007); and Lincoln and Freedom: Slavery, Emancipation, and The Thirteenth Amendment, co-edited with Sarah Vaughn Gabbard.

In addition, Holzer has written more than 400 articles for both popular magazines and scholarly journals, including Life Magazine, American Heritage (where he serves as a Contributing Editor), Civil War Times, American History Illustrated, North & South, Blue & Gray, The Chicago Tribune, The New York Times, and The Los Angeles Times.

Holzer has also written a number of pamphlets and monographs on Lincoln, the latest of which are Lincoln's Deathbed in Art and Memory (with Frank J. Williams, 1998), Lincoln and The Jews (2002), and Standing Tall: The Heroic Image of Abraham Lincoln (2005). And Holzer has contributed chapters to 21 additional books, including Lincoln and His Contemporaries (1999) and The Lincoln Enigma (2001). In 2004, he was the historical advisor to the book Why Lincoln Matters by Mario M. Cuomo.

In February 2007 he helped organize and debut a new "Lincoln Series" of modern political debates and dialogues in the Lincoln tradition at New York's Cooper Union, the first of which featured Mario Cuomo, Newt Gingrich, and Tim Russert, and the most recent of which have or will present John Edwards and Rudy Giuliani. 

A frequent guest on television, Holzer has appeared often on C-SPAN's Washington Journal as well as on the 2005 History Channel special Lincoln; on that network's History Center series; a 2006 episode called "Lincoln in New York;" on Abraham Lincoln: A New Birth of Freedom (PBS, 1992), Civil War Journals (A&E, 1994), American Heritage Presents the Lincoln Assassination (History Channel, 1995), A&E's Biography (1996), and The History Channel specials, Assassins: John Wilkes Booth and Investigating History: Lincoln-Man vs. Myth. He has appeared on The Today Show, The Charlie Rose Show, CNBC, Fox News, The News Hour with Jim Lehrer, and CBS Sunday Morning. He appeared on the three-hour C-SPAN American Writers special on Abraham Lincoln, was profiled on the network's three-hour In-Depth series. He was also seen on C-SPAN in broadcasts of his stage presentations Lincoln Seen and Heard with Sam Waterston and Grant Seen and Heard with Richard Dreyfuss. Holzer's appearance on C-SPAN's Booknotes series inspired the 1994 C-SPAN re-creations of the Lincoln-Douglas debates in Illinois, for which Holzer served as historical consultant and on-air commentator. C-SPAN also broadcast the 2004 on-site re-creation of The Cooper Union address, featuring Holzer and Waterston, and in February 2005 a special Lincoln's Birthday-eve performance of Lincoln Seen and Heard live from the White House, hosted by President and Mrs. Bush. He also appeared on the award-winning discussion show Open Mind and on C-SPAN in the performance piece The Lincoln Family Album starring Liam Neeson and Holly Hunter, broadcast from the Library of Congress in Washington. Most recently he helped organize and introduce the C-SPAN broadcast of a Cooper Union dialogue In the Lincoln Tradition. He is currently taping a C-SPAN special on The White House, to air in 2008.

Holzer also lectures before Civil War and Lincoln groups throughout the country. He has delivered the McMurtry Lecture at the Lincoln Museum in Fort Wayne, the Lincoln Shrine Lecture in Redlands, California, and the Frank and Virginia Williams Lecture at LSU/Shreveport. In 2004, he delivered the prestigious Fortenbaugh Lecture at Gettysburg College and the second annual NEH "Heroes of History" lecture at Ford's Theatre in Washington. In 2005, he was the featured speaker at the ceremonies marking the anniversary of Lincoln's Gettysburg Address at the Solidier's Cemetry in Gettysburg, PA.

He has also organized several Lincoln symposia and curated five museum exhibitions of original art, notably the award-winning 1999 Lincoln Museum exhibit Lincoln From Life. He served as lead historian for several exhibitions and symposia at the New York State Museum in Albany, including State of the Union: New York and the Civil War. He will serve as guest historian to the 2009 New York Historical Society Exhibition, Lincoln and New York.

Much honored for his work, Holzer won a coveted Lincoln Prize for his Cooper Union book in 2005. He has four times won the Barondess Award of the Civil War Round Table of New York (1984, 1990, 1993, 2005; plus an honorable mention in 1999 for the exhibition Lincoln from Life). He has also received the Diploma of Honor from Lincoln Memorial University (1988); won the Award of Achievement from the Lincoln Group of New York three times (1988, 1993 and 2004); received a 1988 George Washington Medal from the Freedom Foundation; a 1989 Writer of Distinction Award from the International Reading Association; and a 1993 Award of Superior Achievement from the Illinois State Historical Society, along with an honorary doctorate in humane letters from Lincoln College in 1992. In 1996 he won the first annual award from the Manuscript Society of America for his use of original manuscripts in Dear Mr. Lincoln. The Union Image won the 2000 Newman Book Award of the American Historical Print Collectors Society. In 2002 Holzer received the coveted Nevins-Freeman Award of The Civil War Round Table of Chicago, and his young reader's book, The President is Shot! recently won several awards. In 2006, Holzer was awarded honorary degrees by Illinois College and University of Massachusetts at Dartmouth, and The Lincoln Group of The District of Columbia's annual award of achievement.

From 1991-1996, Holzer served as president of the Lincoln Group of New York, and still serves on its executive committee. He also served on the board of directors of the Abraham Lincoln Association, and on the editorial advisory board of The Lincoln Herald.

Holzer is founding vice chairman and a regular lecturer at The Lincoln Forum, which hosts an annual symposium each year in Gettysburg, and serves on the Board of Directors of the Ulysses S. Grant Association. He is also a member of the Research Advisory Group for the President Lincoln and Soldiers' Home National Monument in Washington, and serves on the board of historical advisors of the Mariners' Museum's U.S.S. Monitor Center in Newport News, Virginia; the Tredegar National Civil War Center Foundation in Richmond; The National Constitution Center in Philadelphia; and the new Gettysburg National Military Park Visitor Center. At the U.S. Lincoln Bicentennial Commission, he will help plan programs and celebrations to mark Lincoln's 200th birthday in 2009.

In February 2006, Holzer was also named co-chairman of The New York State Lincoln Bicentennial Commission by Governor George E. Pataki. A former member of the New York State Council on the Humanities, Holzer was appointed by Gov. Mario Cuomo to the New York State Archives Preservation Trust Board in 1994, and was re-appointed by Gov. Pataki in 1999, and by New York State Senate Minority Leader David Paterson in 2004. In this role he co-organized and served as lead historian for a Union Preserved Civil War symposium in Albany, co-edited two Archives-sponsored books on New York and The Civil War, and hosted events Archives Stage featuring actor Richard Dreyfuss, C-SPAN founder Brian Lamb, actor Sam Waterston, and, this spring historian Doris Kearns Goodwin.

Educated at the City University of New York, Holzer began his career as a weekly newspaper editor for The Manhattan Tribune, a political campaign press secretary for Congresswoman Bella S. Abzug and Governor Mario M. Cuomo, a government speechwriter for New York City Mayor Abraham D. Beame, and as public affairs director for the PBS flagship station WNET.

Holzer currently serves as Senior Vice President for External Affairs at The Metropolitan Museum of Art in New York, the largest and most comprehensive art museum in the western hemisphere. He joined the museum as Chief Communications Officer in 1992 and was named vice president in 1996 and senior vice president in 2005. From 1984 through 1992 he served as Special Counselor to the Director of Economic Development and executive vice president of The New York State Urban Development Corporation in the administration of Governor Mario M. Cuomo.

Holzer lives in Rye, New York with his wife, Edith, director of public affairs for the New York State Council of Child Caring Agencies. The Holzers have two daughters: Meg, an attorney who attended Yale University and NYU Law School, and Remy, a Harvard graduate with a Masters in Film Studies from NYU who recently served as Editorial Director of Museum of The Moving Image of New York; she is married to New York Sun book critic Adam Kirsch; their son, born September 21, 2007, is Charles Ezra Kirsch.