His first book, Hard News: The Scandals at the New York Times and Their Meaning for American Media (Random House, 2004) grew out of reporting he did as a senior writer at Newsweek in 2002 and 2003.

It uses the Jayson Blair plagiarism and fabrication scandal to conduct a broader examination of the troubles during the Howell Raines administration at the New York Times.

It received overwhelmingly positive reviews from New York magazine ("richly dramatic, hugely entertaining"),[4] Entertainment Weekly ("vigorous, purposeful prose and a killer knack for building suspense"), the Los Angeles Times ("two terrific books in one: a riveting thriller...and a Shakespearean tragedy"), and the Washington Post ("hard to put down...reads like a thriller"[5]), among other places, and the book prompted Hunter S. Thompson to say Mnookin was "one of the best and brightest journalists of this ominous, post-American century.

[10] After Epstein left the Red Sox for the Chicago Cubs, he made an apparent reference to the book when he talked about the difficulty of dealing with "the monster" of fan and ownership expectations for a championship team every year.

He also highlights the Cedillo v. Secretary of Health and Human Services, beginning on June 11, 2007, in which the Cedillo family's lawsuit made the claim that Thiomersal, a compound found in Hepatitis B, DPT, and Hib vaccines, weakened their daughter's immune system such that the live measles virus found within the MMR vaccine overwhelmed her system and thereby caused Autism.

Wakefield is repeatedly mentioned, as is celebrity advocate against vaccination Jenny McCarthy, often in the context of anecdotes by parents outraged by the often one-sided exposure given to these figures in the media.

[13] The New York Times called it a "tour de force" and wrote that "[p]arents who want to play it safe, but are not altogether sure how, should turn with relief to this reasoned, logical and comprehensive analysis of the facts.

[16] It won the New England Chapter of the American Medical Writers Association's Will Solimene Award for Excellence and the National Association of Science Writers 2012 "Science in Society" Award[3] In 2011 Mnookin also brought out an Australian edition with a new preface which directly takes on the situation in Australia, documenting the behavior of antivaxxer Meryl Dorey and relaying the story of the McCafferys, who lost their four-week-old daughter Dana due to pertussis and low vaccination rates.