“The Andy Griffith Show” has never left the airwaves since the first episode aired about 60 years ago.

There are a lot of reasons why a TV show that quit airing new episodes more than a half century ago remains popular. There’s a reason why the first five seasons – the black-and-white episodes – are so beloved and the latter three seasons of color episodes range somewhere between no interest to loathing.

In his book, “Andy & Don: The Making of a Friendship and a Classic American TV Show,” author Daniel de Vise claims the magic was the relationship on the air and off of characters Sheriff Andy Taylor and his deputy Barney Fife played by Griffith and Don Knotts.

De Vise chronicles their similar upbringings in Southern towns – Griffith in Mount Airy, N.C., and Knotts in Morgantown, W.Va. How they rose to Broadway fame and met while performing in “No Time for Sergeants,” a play that starred Griffith and featured Knotts as a supporting cast member.

They became friends then and when Griffith got a shot playing the sheriff of a small town on TV, Knotts called him and said Andy Taylor needed a deputy. The friendship deepened and de Vise lays claim that one of the greatest comic teams of the 20th century was born.

Working with Knotts, Griffith restrained the early buffoonery of the country sheriff. Griffith and Andy Taylor became the straight man for Knotts and Barney Fife. 

When Knotts left the show after the fifth season, which also marked the transition from black-and-white to color TV, the “Griffith Show” lost its magic.

“Andy & Don” is a good book. It captures the magic of the relationship between Griffith and Knotts, possibly the most important relationship in either man’s life. While the friendship between the two men was as real as the relationship between Andy and Barney, the real-life Andy and Don were not their characters. They were very different men than the characters they played in Mayberry.

Both men were plagued with troubles and doubts and had to continue trying to work in the shadow of the “Griffith Show” in the later decades of their lives. At times, the book is a bleak read.  

But the magic of their friendship shines through until the end.