Shortly after release,
Cosmos became the best-selling science book ever published in the English language, and was the first science book to sell more than half a million copies.
Cosmos spent 50 weeks on the
Publishers Weekly best-seller's list, and 70 weeks on the
New York Times Best Seller list.
Cosmos sold over 900,000 copies while on these lists, and continued popularity has allowed
Cosmos to sell about five million copies internationally. Shortly after
Cosmos was published, Sagan received a $2 million advance for the novel
Contact. The success of
Cosmos made Sagan "wealthy as well as famous." It also ushered in a dramatic increase in visibility for science books, opening up new options and readership for the previously fledgling genre. Lewenstein also noted the power of the book as a recruitment tool. Along with
Microbe Hunters and
The Double Helix, he described
Cosmos as one of the "books that people cite as 'Hey, the reason I'm a scientist is because I read that book'." Particularly in astronomy and physics, he said, the book inspired many people to become scientists. Sagan has also been called the "most successful popularizing scientist of our time," for his ability to draw such a large and varied audience. The popularity of Sagan's
Cosmos has been referenced in arguments supporting increased space exploration spending. Sagan's book was also referenced in Congress by
Arthur C. Clarke in a speech promoting an end to Cold War anti-ICBM spending, instead arguing that the anti-ICBM budget would be better spent on Mars exploration. ==Critical reception==