Subtitled "An Observer's Guide to the Universe Beyond the Solar System," the Celestial Handbook combines a lengthy introduction to astronomy with catalog information for every constellation in the sky.

[2][5] Originally self-published in a loose-leaf serial format beginning in 1966, and with a revised edition by Dover Publications in 1978, the Celestial Handbook was well reviewed in amateur astronomy magazines and became a best seller in this specialized field.

[2] Due to the popularity of Celestial Handbook, Tony Ortega writing in the Phoenix New Times in 1997 described Burnham as an author "whose name has become so familiar to some readers it has become a sort of shorthand, like Audubon to birders, Hoyle to card players, Webster to poor spellers, Robert to parliamentarians.

[5] Writing for the Frosty Drew Observatory in 2000, Doug Stewart said: Had Burnham been a more astute businessman he might easily have parlayed his justifiable fame into a comfortable income.

Despite being the author of a successful book, Burnham spent the last years of his life in poverty and obscurity[5] in San Diego, California, selling his paintings of cats at Balboa Park.

The fans of Celestial Handbook were likely unaware of his personal circumstances; possibly assuming that a different and unrelated Robert Burnham, an editor at Astronomy magazine, was the author.

[2] After his death, it was realized that he had often attended programs presented by the San Diego Astronomy Association (at the Ruben H. Fleet Space Theater in Balboa Park) without anyone recognizing him.

[citation needed] In spite of the tragedy of his later years, Burnham continues to be remembered by a generation of deep sky observers for his unique Celestial Handbook.

[2] In 2009 a memorial consisting of a small bronze plaque resembling a page in Burnham's Celestial Handbook was installed on the Pluto Walk at Lowell Observatory.

A much longer version of this essay, An Interview with the author of The Celestial Handbook, dated April 1983, was discovered among Burnham's papers and it was first published in its entirety by The Village Voice in June 2011, 18 years after his death.

[16] It was introduced as follows: If Burnham's life ended in an unfortunate fashion, in the following essay you will meet the man at his most beguiling, a largely self-taught polymath who could be both playful and cantankerous.