The Maestro Myth (1991) charts the history of conducting from its rise as an independent profession in the 1870s to its subsequent preoccupations with power, wealth and celebrity. When the Music Stops (US title: Who Killed Classical Music, 1997) is the first documented history of the classical music business, presenting an exposé of its backstage workings and predicting the collapse of the record industry. Maestros, Masterpieces and Madness: The Secret Life and Shameful Death of the Classical Record Industry (US title: The Life and Death of Classical Music, 2007) is billed as an inside account of the rise and fall of recording, combined with a critical selection and analysis of 100 discs and 20 recording disasters.

Lebrecht has written about the composer Gustav Mahler, including in books Mahler Remembered (1987) and Why Mahler? (2010). His interest in contemporary music is reflected in The Complete Companion to 20th Century Music (2000) and in the Phaidon Press series of 20th century composer biographies, of which he was founder and editor.

Other books on music he has written include The Book of Musical Anecdotes (1985), Music in London (1992), and Covent Garden: The Untold Story (2000).

His career as a novelist began with The Song of Names, a tale of two boys growing up in wartime London, which was published in 2001 and went on to win the 2002 Whitbread Award for First Novel. His second novel, The Game of Opposites, was published in 2009.

Lebrecht's polemical writings have often drawn fierce responses. While Robert Craft praised The Maestro Myth as an "exposé of the business practices of orchestral conducting (that) is likely to be the most widely read classical music book of the year," the opera critic Michael Tanner wrote in The Times Literary Supplement that "this may be the most disgusting book I have ever read". Lebrecht was described by musicologist Richard Taruskin as "a sloppy but entertaining British muckraker". Although many eminent conductors from Vladimir Ashkenazy and Daniel Barenboim to William Christie and Franz Welser-Möst maintain cordial relations with Lebrecht and appear in his radio shows, an anonymous informant identified as "one of the world's leading conductors" told The Independent that Lebrecht had for years been getting away with "pompous, preposterous judgment" and "inept research".

In When the Music Stops (pp. 421—425) he published the concert fees earned by top artists, and in Maestros, Masterpieces and Madness (pp. 136—140) he revealed the true sales figures for classical records.

In October 2007 the founder of Naxos Records, Klaus Heymann, sued Lebrecht's publisher, Penguin Books, for defamation in London's High Court of Justice. Heymann claimed that Lebrecht had wrongly accused him of "serious business malpractices" in his book Maestros, Masterpieces and Madness, and identified at least 15 statements he claimed were inaccurate. The case was settled out of court. As a result of the settlement, Penguin issued a statement apologizing for "the hurt and damage which [Heymann] has suffered". The publisher also agreed to pay an undisclosed sum in legal fees to Heymann, to make a donation to charity, to refrain from repeating the disputed allegations and to seek the return of all unsold copies of Lebrecht's book. Commenting on the affair, Heymann said that "For me it’s beyond belief how any journalist in five pages can make so many factual mistakes. It’s shocking. Also, he [Lebrecht] really doesn’t understand the record business." The settlement did not extend to the US edition of Lebrecht's book, but Heymann vowed to seek its withdrawal in the United States, saying "The book made me look like a shit, so something had to be done. When Lebrecht talks to people he doesn't take notes so he confuses and confounds what people say." In fact, Heymann took no action against the US edition of the book.

In the early blogosphere, Lebrecht was critical of some online trends, arguing in his Evening Standard column that "Until bloggers deliver hard facts paid for newspapers will continue to set the standard as the only show in town". One blogger used this statement to charge Lebrecht with hypocrisy in light of the Heymann suit. Despite his early criticism of classical music blogs, Lebrecht launched his own blog, Slipped Disc, in March 2007 and was a keen proponent of social media in his BBC shows.