Disaffected Robert B. Parker readers are a lot like restaurant customers who gradually take consistency for granted.

When asked why they don't patronize a certain establishment anymore, diners are apt to say something like, "the food hasn't changed!"

The same applies to Mr. Parker's long-running Korean-war vet cum knight errant, Spenser.

The Boston private eye's personal code hasn't changed. His warrior bond with the enigmatic gangster Hawk is the same. As is his love for psychotherapist Susan Silverman and smart-ass one-liners, which seem to be on an even par.

In the latest installment, Back Story, Spenser is asked to solve a nearly 30-year old bank robbery-turned murder case.

He does so, through the usual tough guy tactics, mongrel persistence and episodes of personal danger. He kills a few people, too.

Throughout the novel, a quick read due to Parker's dialogue-heavy style, Spenser remains true to the character created more 30 years ago.

Perhaps the books have grown predictable, and the characters exhibit tongue-in-cheekiness to the point of terminal noir lockjaw. Or perhaps, having read so many of the stories we are overfamiliar with the terrain. The dish tastes the same.

However. If you are looking for a fun, tricky mystery with engaging characters, Chef Parker has prepared yet another in a long line of satisfying offerings.