"An inventive espionage thriller set before World War I . . . A twist-filled adventure that proves far from elementary."
―Tom Nolan, The Wall Street Journal
"Just when it seems that Sherlock Holmes-inspired books are old hat, along comes this thrill ride of espionage, conspiracy, murder, and yes, even romance, set in 1909 London. Both fans of Sherlock Holmes and spy novels will enjoy this debut by a former screenwriter peppered with historical figures like Winston Churchill, especially when the ending hints of more adventures for the first British double-0 agent ever."
―Barbara Clark-Greene, Library Journal
"Lyle offers a skillful blend of fact and fiction, from Holmes and Watson to Churchill and the real-life leaders of the agencies that became MI5 and MI6. A compelling series debut and a natural read-alike for Robert Goddard's Max Maxted series and David Downing's Jack McColl series."
"Handsomely crafted . . . The villains here are world class, with German munitions giants, Russian anarchists, and a couple of rather unexpected conspirators as well. Lyle achieves a nice blend of history and mystery, with cameo appearances by such fictional and real-life luminaries as Holmes and Winston Churchill."
―Bookpage WhoDunit Column
Fans of Arthur Conan Doyle's stories will remember young Wiggins as the leader of the Baker Street Irregulars . . . Though Lyle's debut novel is certainly an homage, it's not a flat-footed imitation but a crisp, stylish spinoff."
"An entertaining blend of history and fiction . . . Lyle's descriptions of 1909 London are vivid. One can almost smell the coal smoke and the raw sewage. The Irregular is a compelling book, one to add to one's reading list."
―New York Journal of Books
"I think H.B. Lyle is probably our most talented historical mystery writer today. An author who writes like a veteran but instead brings a fresh new perspective."―Andrew Gulli, Strand Magazine
"H.B. Lyle has found the golden thread between Holmes and Bond in a thriller that engages on every page."
―Giles Foden, author of The Last King of Scotland
"A thrilling story of espionage, murder, and the creation of the Secret Service."―Charles Cumming, author of A Divided Spy