Kevin Hershberger
В роли: Dr. Jones, medicine episode ca. 1846

Stephanie Elisabeth Raven
В роли: Violin Student

Louise Rusnak
В роли: Librarian

Jeffrey F. Smith
В роли: William Harvey, medicine episode

Kathryn Coombs
В роли: Barbara McClintock, also background extra

Bill McIntosh
В роли: Copernicus

James Thompson
В роли: Michael Faraday, physics episode

Ron Hawkins
В роли: Wilhelm Roentgen, medicine & chemistry episodes

Kathryn Kent
В роли: Mrs. Roentgen, medicine & chemistry episodes

Charlie Leveridge
В роли: Boy with Diabetes

Daniel McMichael
В роли: Charles Darwin

Henry Raven
В роли: Small Pox Child

Buzz Mooney
В роли: 1820s surgery attendant, Evolution & Medicine episodes

Билл Най
В роли: Host

John Pagano
В роли: Dr. William Morton

Jared Morrison
В роли: Hans Krebs, biology episode, and Capt. Robert FitzRoy, evolution episode

Sam Edens
В роли: Sir Isaac Newton

Jim Choate
В роли: Copernicus' Priest, astronomy episode

Ed Mantell
В роли: 18th Century Graverobber

Ben Kullman
В роли: Galileo Galilei, Alfred Wegener

Keith E. Whitehead
В роли: Zoologist Eduard Van Beneden - Biology Episode

Stephen Wolfsberger
В роли: Dmitry Mendeleyev, Chemistry episode

Rob Gibson
В роли: Henri Becquerel, chemistry episode

Paul Bugelski
В роли: Johannes Keppler

Kurt Grauf
В роли: Patient

Austin Murray
В роли: John Dalton