Illustration by David A. Johnson

From James Bond to Raylan Givens, some of the great literary heroes of all time live on even after their original creator passes. Whether given new life in posthumous novels or on-screen, these characters — luckily for fans and followers — refuse to die.

When Sir Arthur Conan Doyle grew weary of concocting diabolical mysteries for the eccentric gumshoe Sherlock Holmes, the author simply threw the supersleuth to his death at Reichenbach Falls in the 1893 short story The Final Problem. Less than a decade later, Holmes lived again in The Hound of the Baskervilles — and cheated death once more in the 1903 short story The Adventure of the Empty House.

Why was Doyle forced to breathe new life into Holmes? Elementary, my dear Watson: Rabid fans demanded the beloved crime solver die another day, and publishers were not about to let their quirky cash cow rest in peace. Indeed, since Doyle himself shook this mortal coil in 1930, the Baker Street irregular has proved to be as perennial as poppies, inspiring hundreds of posthumous iterations, including a 1954 volume of stories by Doyle’s own son, Adrian Doyle. In fact, according to Guinness World Records, Holmes is the most portrayed movie character, with more than 70 actors playing the role in more than 200 films and television shows.

In contemporary publishing, literary heroes like James Bond, Mike Hammer, Jason Bourne, Raylan Givens and Spenser, among countless others, have proved to be similarly immortal when their creators are not, enjoying apparently infinite cliff-hanging adventures even after the original author has been laid to rest. This spring and summer alone will bear witness to the ­publication of a new Hammer thriller, King of the Weeds; another Bourne installment, The Bourne Ascendancy; and an additional Spenser mystery, Cheap Shot, despite the fact that the series’ creators — Mickey Spillane, Robert Ludlum and Robert B. Parker, respectively — are long gone.

“I think it’s the ultimate compliment to an author that their audience wants more of their creations even after they’ve left this world,” says Pulitzer Prize-nominated Ace Atkins, who took over the Spenser mystery series after creator Parker died in 2010.

“Some characters dig very deep hooks into the public consciousness,” says Eric Van Lustbader, the author of 25 international best-sellers who has penned nine Bourne adventures since Ludlum’s 2001 passing. “For readers, these books allow them to stay connected to characters they really love, and for publishers, in most cases, these books make very good business sense.”

Indeed, in an increasingly volatile publishing industry in which hardcover book sales have recently been on the decline, there is a keen financial imperative to maintain and continue these blue-chip franchises, which routinely clamor up the best-seller lists and stoke ongoing interest in the original titles. It’s a business model akin to Hollywood’s propensity for adding Roman numerals to premises that clicked once and well with audiences — and arguably no more dubious than recasting the role of 007 five times to keep the Bond franchise sharpshooting at the box office. (Bond, ­incidentally, was featured in only 14 novels penned by creator Ian Fleming, though the debonair spy has served her majesty’s secret service in almost 40 novels penned by at least seven authors since Fleming’s 1964 passing.)

For the authors who pen these books — derogatorily dubbed “delegated sequels” or “rented premises” by harsher critics — the paydays can be more substantial than for their own original fare, while oftentimes the branded books create crossover interest to an author’s other tomes. Frequently, carrying on a legacy character provides these authors a certain wish fulfillment; the opportunity to spin new yarns for heroes they’ve long loved.