... it gets complicated—maybe too complicated ... Wolfe fans will spend a lot of time discussing this. All the best detective stories have clues buried deep in them. You need to look back and check for the ones you missed. It’s an enigmatic final note from sci-fi’s most enigmatic author.
... what initially seems a straightforward mystery quickly soars off in unexpected directions, both in terms of plot and of narrative trickery ... While there is much familiar Wolfe imagery throughout the novel...there is also an almost overwhelming sense of compromise with mortality ... but there is also the hint of treasures brought from distant worlds, which is something else Wolfe was pretty good at. Interlibrary Loan is, like most of Wolfe’s final novels, more intimate in scope and restrained in style than his celebrated masterpieces, but it’s a fitting and suitably twisty rumination on which to end an astonishing career.
Wolfe died in 2019 at age 87; this posthumous sequel to A Borrowed Man blends a hard-boiled mystery style with a sf future and is mostly successful. While this can be read as a stand-alone, familiarity with the main character’s background story may bring more clarity for readers.