A clued-in friend, spotting this book in my bag, asked if Eva Gabrielsson could be exaggerating her relationship with Dragon Tattoo author Stieg Larsson.

But her jigsaw account of their lives – and especially her grief in the two years after Larsson died in 2004 aged 50 – places Eva beyond doubt as this complex Swedish writer’s life partner.

Also clear in this book is the unfairness of Swedish inheritance law not recognising unmarried childless couples: Eva has been robbed of the right to steer his Millennium Trilogy in the direction Larsson would have wanted.

Architect Gabrielsson says they planned to marry in 1983 but work intervened – although they wore wedding rings anyway. two decades later, they discussed marrying for their 50th birthdays – and again let it slip.

Aside from work, she cites their combined early sense of abandonment as a major factor in not having children. but don’t forget that Stieg’s father and brother, Erland and Joakim, couldn’t have inherited everything if Larsson hadn’t died intestate. nor did Stieg monitor (despite Gabrielsson’s reminders) whether Millennium publisher Norstedts had created the promised joint company for Stieg and Eva – which would have given Eva legal literary rights as a co-founder.

Either of these commonsense deeds by Stieg Larsson (right) would have bridged the morass into which his bereaved partner fell. Yet anger against her lover is notably absent in this book. Instead, Eva feels useless for being unable to safeguard his legacy.

Agreed, Larsson could not have foreseen the success of Lisbeth ‘Dragon Tattoo’ Salander, Mikael Blomkvist et al in his three doorstopper books – not to mention the blockbuster films. but he lived a stressful, caffeine-laden, junk-food lifestyle. He was a global public opponent of neo-Nazism: death-threats included bullets in the post. Surely making a will was dazzlingly obvious for such an intelligent man?

Hindsight aside, the raison d’etre for Stieg -amp; me is the Millennium Trilogy, and Gabrielsson’s book is threaded with examples of how the people, places, things and events in all three thrillers were drawn from their joint experiences together.

Retribution was one of Larsson’s driving forces, and it permeates the Millennium Trilogy and Stieg -amp; me.

He was scarred as a teenager after witnessing a gang rape but not intervening, Gabrielsson writes, adding: “The Millennium Trilogy is a catalogue of all forms of violence and discrimination endured by women.”

And Eva clearly shares Stieg’s passion for revenge: on new Year’s Eve 2004 she conducted a fascinating feral Viking ‘nio’ ceremony to curse his enemies. although no one is named, it’s hard to see how father Erland and brother Joakim escaped the hit-list.

It was not until October 2007 that they deeded Gabrielsson their half of the Stockholm apartment she and Stieg bought in 1991.

Stieg -amp; me is not a riveting book in terms of style or prose. It’s stilted in parts and frequently doesn’t finish the point. but it’s essential reading for the bigger picture of this bestselling author and campaigner: his search for identity and his idealism in the face of constant struggle.

It is also a solid love story, steeped in common beliefs, shared interests and mutual attraction – plus an achingly sharp account of grief and attempted recovery.

At its darkest, Stieg -amp; me is a chilling tale of immorality and unfairness, etched with blind stupidity on vital practical details.

The heart-breaking repercussions of the latter are more than anyone should ever have to bear.

An achingly sharp portrait of grief, injustice and the thirst for revenge