# I Know This Much Is True (miniseries)
*I Know This Much Is True* is a six-part American limited drama series for HBO, adapted from Wally Lamb's 1998 novel of the same name and written and directed by [Derek Cianfrance](https://www.edgepedia.org/derek-cianfrance). It stars [Mark Ruffalo](https://www.edgepedia.org/mark-ruffalo) in a dual lead role as identical twin brothers Dominick and Thomas Birdsey, following their parallel lives in a story of betrayal, sacrifice, and forgiveness set against twentieth-century America.[1](https://www.latimes.com/entertainment-arts/tv/story/2020-05-17/mark-ruffalo-i-know-this-much-is-true-hbo-wally-lamb) • [2](https://lumiere-a.akamaihd.net/v1/documents/wandavision_production_brief_final_01-06-21_8766810b.pdf) The series premiered on HBO on May 10, 2020.[3](https://time.com/5832815/i-know-this-much-is-true-mark-ruffalo-review/)
| Key fact | Detail |
|---|---|
| Format | Six-episode limited series on HBO, written and directed by Derek Cianfrance[1](https://www.latimes.com/entertainment-arts/tv/story/2020-05-17/mark-ruffalo-i-know-this-much-is-true-hbo-wally-lamb) |
| Premiere | May 10, 2020, on HBO[3](https://time.com/5832815/i-know-this-much-is-true-mark-ruffalo-review/) |
| Source | Wally Lamb's 1998 bestseller, more than 900 pages long and selected for Oprah Winfrey's book club[1](https://www.latimes.com/entertainment-arts/tv/story/2020-05-17/mark-ruffalo-i-know-this-much-is-true-hbo-wally-lamb) |
| Lead performance | Mark Ruffalo plays both identical twins, Dominick and Thomas Birdsey, and executive produced[1](https://www.latimes.com/entertainment-arts/tv/story/2020-05-17/mark-ruffalo-i-know-this-much-is-true-hbo-wally-lamb) |
| Principal cast | Melissa Leo, John Procaccino, Rosie O'Donnell, Archie Panjabi, Imogen Poots, Juliette Lewis, and Kathryn Hahn[2](https://lumiere-a.akamaihd.net/v1/documents/wandavision_production_brief_final_01-06-21_8766810b.pdf) |
| Reception | 74% on the Rotten Tomatoes Tomatometer from 57 reviews; 87% from more than 250 audience ratings[4](https://www.rottentomatoes.com/tv/i_know_this_much_is_true/s01) |
| Recognition | Ruffalo's performance in the series won an Emmy[5](https://www.cinemablend.com/television/critics-have-seen-mark-ruffalos-task-getting-praise-hbo-show) |
## Premise
The series centers on Dominick and Thomas Birdsey, identical twins who grow up with their mother ([Melissa Leo](https://www.edgepedia.org/melissa-leo)) and stepfather (John Procaccino) in a [Connecticut](https://www.edgepedia.org/connecticut) working-class town, in a home marked by tension and occasional violence.[1](https://www.latimes.com/entertainment-arts/tv/story/2020-05-17/mark-ruffalo-i-know-this-much-is-true-hbo-wally-lamb) An event sets Dominick on a journey to track the family's tortured history back to the early wave of Italian immigrants who arrived in the United States in the early twentieth century.[6](https://entertainmentvoice.com/2020/05/10/derek-cianfrance-on-adapting-wally-lambs-sprawling-opus-for-hbos-i-know-this-much-is-true/) In the novel, the twins' maternal grandfather, the Italian immigrant Domenico Tempesta, narrates an "autobiography" juxtaposed against the main narrative.[7](https://www.kirkusreviews.com/book-reviews/wally-lamb/i-know-this-much-is-true/)
The brothers were born six minutes apart on opposite sides of midnight on [New Year's Eve](https://www.edgepedia.org/new-years-eve) 1950, giving them separate birthdays and, as students during the [Vietnam War](https://www.edgepedia.org/vietnam-war), divergent draft numbers. When the story begins they are 40 years old.[3](https://time.com/5832815/i-know-this-much-is-true-mark-ruffalo-review/) Thomas's literal interpretation of the biblical verse "And if thy right hand offend thee, cut it off" anchors the story's religious symbolism.[3](https://time.com/5832815/i-know-this-much-is-true-mark-ruffalo-review/)
## Development
The novel's path to the screen ran through two decades.
**Ruffalo's rescue of the project.** Mark Ruffalo held an option on the novel and was looking for a writer-director to collaborate with on a small-screen adaptation; he reached out to Derek Cianfrance, whose films *[Blue Valentine](https://www.edgepedia.org/blue-valentine-film)* (2010) and *The Place Beyond the Pines* he knew, and Cianfrance was drawn to the story's concern with family connection.[8](https://www.screendaily.com/features/derek-cianfrance-on-making-mark-ruffalo-hbo-series-i-know-this-much-is-true/5149697.article) According to the Los Angeles Times, Ruffalo helped rescue the project from development limbo.[1](https://www.latimes.com/entertainment-arts/tv/story/2020-05-17/mark-ruffalo-i-know-this-much-is-true-hbo-wally-lamb)
Cianfrance argued that the book's scale demanded television. He described the novel as a thousand-page book and said the TV medium allowed the story to expand in the way HBO had a history of doing with such projects.[9](https://medium.com/warnermediaent/i-know-this-much-is-true-writer-director-derek-cianfrance-on-storytelling-process-31324ae3e556) Lamb was generous in letting him take over the transposition, telling him not to feel beholden to the book.[10](https://www.money-into-light.com/2021/03/derek-cianfrance-on-i-know-this-much-is.html) Cianfrance completed post-production while confined at home during the COVID-19 pandemic.[8](https://www.screendaily.com/features/derek-cianfrance-on-making-mark-ruffalo-hbo-series-i-know-this-much-is-true/5149697.article)
## Production and performance
Ruffalo, who also executive produced, played both twins and bulked up in real life for the roles, a physical commitment he had previously made for the Hulk films.[1](https://www.latimes.com/entertainment-arts/tv/story/2020-05-17/mark-ruffalo-i-know-this-much-is-true-hbo-wally-lamb) • [11](https://www.aarp.org/entertainment/television/mark-ruffalo-i-know-this-much-is-true/) Critics singled out the dual performance: Time called it "two performances of a lifetime,"[3](https://time.com/5832815/i-know-this-much-is-true-mark-ruffalo-review/) and the trade press later described it as his Emmy-winning turn in the series.[5](https://www.cinemablend.com/television/critics-have-seen-mark-ruffalos-task-getting-praise-hbo-show)
## Reception
On Rotten Tomatoes the miniseries holds a 74% Tomatometer from 57 reviews and an 87% Popcornmeter score from more than 250 audience ratings. The site's critics consensus says the relentlessly grim plotting makes it a difficult watch, but that the strength of Ruffalo's dual performances makes it a dark tale worth tuning into.[4](https://www.rottentomatoes.com/tv/i_know_this_much_is_true/s01)
Reviewers divided over the show's relentlessness. The Independent's Ed Cumming found the six-part series brilliantly acted but "impossible to recommend," writing that there was simply enough despair in the atmosphere.[12](https://www.the-independent.com/arts-entertainment/tv/reviews/i-know-this-much-is-true-episode-1-review-mark-ruffalo-hbo-sky-atlantic-a9508351.html) RogerEbert.com called the adaptation often "too much" in its unremitting misery, trauma, and tragedy, while praising its riveting performances.[13](https://www.rogerebert.com/reviews/i-know-this-much-is-true-movie-review-2020) Time's reviewer credited Ruffalo with redeeming an otherwise maudlin series.[3](https://time.com/5832815/i-know-this-much-is-true-mark-ruffalo-review/) In France, *Le Monde* described the series as a suffocating tragedy and noted the novel's French publication in 2000 as *La Puissance des vaincus* (Belfond/Livre de poche).[14](https://www.lemonde.fr/culture/article/2020/05/19/musicale-epuree-etouffante-sociale-une-semaine-de-series_6040059_3246.html)
## Differences from the novel
The adaptation is largely faithful to Lamb's vision, according to Kirkus, but it omits at least one disturbing episode: in the book, Dominick rapes Dessa while they are dating, a detail missing from the miniseries.[15](https://www.kirkusreviews.com/news-and-features/articles/i-know-this-much-is-true-trouble-follows/) Reviewers also judged that the late flashback to the grandfather's life story worked better in the book than on screen.[13](https://www.rogerebert.com/reviews/i-know-this-much-is-true-movie-review-2020)
## References
1. [HBO 'I Know This Much Is True': Read the note that got it made, Los Angeles Times](https://www.latimes.com/entertainment-arts/tv/story/2020-05-17/mark-ruffalo-i-know-this-much-is-true-hbo-wally-lamb)
2. [WandaVision production brief (Kathryn Hahn biography), WarnerMedia](https://lumiere-a.akamaihd.net/v1/documents/wandavision_production_brief_final_01-06-21_8766810b.pdf)
3. [Mark Ruffalo Gives Two Performances of a Lifetime in HBO's I Know This Much Is True, Time](https://time.com/5832815/i-know-this-much-is-true-mark-ruffalo-review/)
4. [I Know This Much Is True: Miniseries, Rotten Tomatoes](https://www.rottentomatoes.com/tv/i_know_this_much_is_true/s01)
5. [Critics Have Seen Mark Ruffalo's Task, And He's Getting A Ton Of Praise For The HBO Show, CinemaBlend](https://www.cinemablend.com/television/critics-have-seen-mark-ruffalos-task-getting-praise-hbo-show)
6. [Derek Cianfrance on Adapting Wally Lamb's Sprawling Opus for HBO's 'I Know This Much Is True', Entertainment Voice](https://entertainmentvoice.com/2020/05/10/derek-cianfrance-on-adapting-wally-lambs-sprawling-opus-for-hbos-i-know-this-much-is-true/)
7. [I Know This Much Is True (book review), Kirkus Reviews](https://www.kirkusreviews.com/book-reviews/wally-lamb/i-know-this-much-is-true/)
8. [Derek Cianfrance on making Mark Ruffalo HBO series 'I Know This Much Is True', Screen Daily](https://www.screendaily.com/features/derek-cianfrance-on-making-mark-ruffalo-hbo-series-i-know-this-much-is-true/5149697.article)
9. [I Know This Much Is True: writer-director Derek Cianfrance on storytelling process, WarnerMedia Entertainment on Medium](https://medium.com/warnermediaent/i-know-this-much-is-true-writer-director-derek-cianfrance-on-storytelling-process-31324ae3e556)
10. [Money Into Light: Derek Cianfrance on 'I Know This Much Is True' and his career (Part 1 of 4)](https://www.money-into-light.com/2021/03/derek-cianfrance-on-i-know-this-much-is.html)
11. [Mark Ruffalo Plays Twins in 'I Know This Much Is True', AARP](https://www.aarp.org/entertainment/television/mark-ruffalo-i-know-this-much-is-true/)
12. [I Know This Much Is True review: Gloomy show is brilliantly acted but impossible to recommend, The Independent](https://www.the-independent.com/arts-entertainment/tv/reviews/i-know-this-much-is-true-episode-1-review-mark-ruffalo-hbo-sky-atlantic-a9508351.html)
13. [I Know This Much is True movie review, RogerEbert.com](https://www.rogerebert.com/reviews/i-know-this-much-is-true-movie-review-2020)
14. [« Homecoming », « I Know This Much Is True », « Little Fires Everywhere » : une semaine de séries télé, Le Monde](https://www.lemonde.fr/culture/article/2020/05/19/musicale-epuree-etouffante-sociale-une-semaine-de-series_6040059_3246.html)
15. [I Know This Much Is True: Trouble Follows, Kirkus Reviews](https://www.kirkusreviews.com/news-and-features/articles/i-know-this-much-is-true-trouble-follows/)
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*Topic: Encyclopedia › Arts and culture › Literature and written works › Creative written works and worlds › Adaptations, tie-ins, and fictional worlds › Works adapted from novels › TV series and shows based on novels*
*Initially written Sep 17, 2026 · Reviewed: Oct 25, 2026 · Edited: Oct 15, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license