Ancient Greek Thinkers (Early Science): Figures like Pythagoras, Archimedes.
Renaissance and Scientific Revolution:
Leonardo da Vinci (for his scientific observations and inventions)
Tycho Brahe (astronomy)
Galileo Galilei (astronomy, mechanics)
Johannes Kepler (planetary motion)
Isaac Newton (mechanics, optics, gravitation)
18th and 19th Century Physics and Chemistry (Classical Physics):
Notable figures from various fields like:
Electromagnetism (e.g., Faraday, Maxwell, Hertz)
Thermodynamics
Optics
Early atomic theory
Likely to include scientists like:
Robert Boyle
Antoine Lavoisier
Alessandro Volta
Hans Christian Ørsted
Georg Ohm
Michael Faraday
James Clerk Maxwell
Heinrich Hertz
Hermann von Helmholtz
Lord Kelvin

First published in German as "Grosse Naturforscher" and translated into English in 1933, the book presents a series of biographical sketches of approximately seventy "outstanding investigators." Lenard, a Nobel laureate in Physics (1905), focuses almost exclusively on physical scientists, with only a few biological figures included. The book largely covers the history of classical physics, concluding its narrative before the significant breakthroughs of the early 20th century by figures like Rutherford, Planck, Bohr, and Einstein.