Summer reading. Crime novels. Joe Nesbo this year. His Harry Hole fits the crime detective trope of the single, middle-aged, morose, driven misfit too!
Here are just a few of my favourites in this category: Morse, Lewis, Bosch, Wallander, Rebus, Perez, DCI Banks, Frost, Foyle, Cannon, Montalbano, Jesse Stone, George Gently, Longmire.
Readers keep sending more names. Add Vera (fits the bill despite being female) and Jack Irish.