I know zilch about Nick Horby, so I can't make any recommendations based directly on that. However, a while back I went from reading SF and fantasy almost exclusively to reading other types of genre fiction, so I thought I'd throw out some authors I've really enjoyed that you might want to check out, along with short descriptions of recommended novels and an Amazon link. Hopefully one of them will catch your eye!
Laurie King's Mary Russel series starting with
The Beekeeper's Apprentice, a Sherlock Holmes pastiche about a young woman who teams up with Holmes later in his life.
George Macdonald Fraser's
Flashman series, wherein a total bastard tells the history of the British empire in the late 19th century.
Patrick O'Brian's Aubrey/Maturin series beginning with
Master and Commander, top-notch, jargon heavy adventures about the British navy in the late 18th century.
Both Donald Westlake's comedic crime fiction, particularly the Dortmunder series (beginning with
The Hot Rock), and his dead serious Parker series written as Richard Stark (beginning with
The Hunter).
John Le Carre's spy fiction, especially his George Smiley trilogy which kicks off with a deep Cold War riff on Kim Philby in
Tinker, Tailor, Soldier, Spy.
William Marshall's
Yellowthread Street series of surreal police procedurals set in Hong Kong starting in the early 70s. For a more straight-forward procedural, you can't go wrong with
any novel in Ed McBain's 87th Precinct series.
Good luck!
FnordChan
