May 6—Welcome back, Dennis Lehane.

Several years have passed since he wrote his last novel and his return, "Small Mercies," is a brutal yet remarkable story about a mother's vendetta against the criminals who shattered her family and life.

A tour de force.

Lehane is known for gritty novels that explore the lives of criminals and hard-living characters, often set in the Irish neighborhoods of Boston.

His books include "Shutter Island," "Mystic River," "Gone, Baby, Gone," etc. They are usually more than just crime yarns. His novels are about loyalty, codes among gangs and cops and neighborhoods, grief and honor, shards of humanity embedded in fists of violence. They are simultaneously bold and nuanced.

"Small Mercies" is Lehane at his best. Possibly, his very best.

The book is set in 1974 Boston, summertime. The city is boiling in a stew of humidity and a new busing policy to desegregate the city's schools.

Mary Pat Fennessy is white, Irish, already questioning events and her place in her life — middle-aged, dead-end job, utilities cut off, widowed by one husband, abandoned by another, a son dead to heroin — now, after a lifetime and generations of sticking close to Southie, her neighborhood, she has a daughter unhappy about the prospect of being bused across town.

Mary Pat's life unravels from there.

"Small Mercies" is not an easy read. That's not a statement about style. Lehane's style is readable. The book is a page turner. The story is compelling. Lehane reels readers into this world and story.

No, it's not easy because the material is not easy. Lehane pens an uncompromising look at racism — Boston and 1974 serve as a microcosm of an American travesty throughout the nation's history and how easily people can misplace their loyalties to people and place. Characters utter slurs and racial epithets on every page, reflective of a fear, anger and hate that is not even given a second thought because it has been stamped into their souls.

While Mary Pat confronts the men who brutally alter her world, she must face the prejudices that thread through her like poisoned veins.

Lehane waters nothing down. He pens a thriller framed in a much deeper exploration into the human landscape.