I am so grateful for the many people who have shared their stories for inclusion in this book. Some of those people are:

The five children in The Berry family are my youngest set of interviewees. The family of All American athletes was created when Peter, Aaron, and Willa’s parents died in a car crash in 2011, causing them to live with cousins Noah and Willa and their parents, Simone and Matt. Peter and Aaron, paralyzed from the waist down, became All American wheelchair basketball players. Willa is on her way as an outstanding high-school soccer player. Noah and Misha are internationally ranked tennis players. Together, the seven of them have founded OLIE: One Life is Enough to fight distracted driving.

Dave and Glenn Dahl are the brothers who built “Dave’s Killer Bread.” After Dave spent 15 years in prison for committing four felonies, Glenn hired him back into the family bakery, and they eventually sold the business for more than $200M.

LetsEngage.com founders Daniel Hennes, Noah Schwartz, and Jake Olson, have been friends since their freshman years of college. When Jake became a highly sought-after speaker as the first blind football player to play in an NCAA Division 1 Game, Daniel became his manager, and the rest is history.

The Harmon family‘s nine exceptional siblings have built a diverse array of businesses including an advertising firm (Harmon Brothers) responsible for 1.3B hilarious ad views and $350M in revenue and many others.

Brett and Dave Kopf are the brothers behind Remind, a messaging platform for teachers that has has 35M+ users and an active teacher in over half of US schools.

Tod and Tim Leiweke are American sports-executive brothers. Tod is currently the founding CEO of the new Seattle NHL hockey team, and Tim is CEO of the Oak View Group, one of its main investors.

Major General Maria (Lodi) Barrett and Brigadier General Paula Lodi are the first two sisters to be promoted to the rank of General in the United States Armed Forces.

Atima and Nyalia Lui are the brother-sister team behind Nudest.co (recently merged with AlgoFace), a platform that uses artificial intelligence to match customers’ skin tone to fashion and beauty items that best complement their complexions.

Bradford and Bryan Manning are Two Blind Brothers both in reality and as a brand: they founded a NYC-based clothing line by that same name and profiled on Ellen. It creates amazing-feeling luxury casual wear. The founders are affected with a form of macular degeneration and pledge 100% of their profits to medical research to cure blindness.

Ali and Hadi Partovi are Iranian-born, identical-twin brothers who have built and invested in some of the most notable Silicon Valley tech startups of our time.

Caroline and Christine Strzalka are first-generation-American sisters who founded ItsByU.com, do-it-yourself arrangement kits with farm-fresh blooms, by subscription.

Seth and Bob Tibbott are the founder and lead investor, respectively, in Tofurky, a company founded in 1980 that has been leading the plant-based diet movement since before it was cool.

Craig Koerner is a research professor in the Strategic and Operational Research Department at the US Naval War College. In our interview, he talks about what “force multiplication” is and isn’t. Force multiplication is the idea behind the book’s inception as well as its title.

Nicholas Paul Brysiewicz is the Director of Development at the Long Now Foundation. In our interview, he talks about creating a long-term mindset useful in the creation of stable partnerships.

In addition to interviews with successful siblings, I have also spoken (pseudonymously) with “control” interviewees who had unsuccessful sibling relationships. Their stories are told using pseudonyms and without any other identifying information.

If you were interviewed and don’t see yourself on this list yet, it’s because I need a signed waiver form to use your name for the book. If you would like to be interviewed as part of the book, please email me at lmusher@gmail.com.