A friend recently asked me how she could learn to write music criticism, and without a moment’s hesitation, I told her there were two new books that I would loan her: Dan Morgenstern’s “Living With Jazz” (Pantheon, 678 pages, $35) and Gary Giddins’s “Weather Bird: Jazz at the Dawn of Its Second Century” (Oxford, 604 pages, $35). My recommendation was not entirely objective, since I have been a friend of both authors for more than 20 years. But, then, no knowledgeable jazz writer could be objective about either of these two giants.

Mr. Morgenstern is the single greatest authority on jazz history, the go-to guy for facts and data. When Phil Schaap doesn’t know the answer to a question, he calls Mr. Morgenstern. Mr. Giddins has been recognized as the Duke, the Count, the Earl of jazz writers for so long that no jazz fan can approach his work with an entirely clean slate. Both their books are collections of work previously published in newspaper, magazine, and liner note formats, though in Mr. Giddins’s case many pieces have been significantly rewritten and expanded.

The two authors are refreshingly untainted by the traditional prejudices of jazz writing. They have no axe to grind against singers, white people, or non-Americans. They find new things to say about canonical figures like Armstrong and Ellington and uncover important players who have fallen between the cracks. Interestingly, though, both of their books begin with introductions that are more autobiographical than I have ever known either man to be.

Mr. Morgenstern, who just turned 75, talks about discovering jazz as a youngster in Austria and then Copenhagen. He weaves in the tale of how he gradually learned about the music with the details of how his family survived the war and gradually made their way to New York in 1947. Mr. Giddins’s childhood doesn’t involve any Nazis, but his musical journey through rhythm-and-blues to Bach to Louis Armstrong seems no less dramatic – especially his vivid description of first hearing the Armstrong-Earl Hines Hot Seven sessions.

For three decades, Mr. Morgenstern has served as the director of the Rutgers Institute for Jazz Studies, contributing to and improving hundreds of works of jazz scholarship, and he has experienced and absorbed more jazz firsthand and on records than anyone else I know. He is also the only one who can write about sitting next to Miles Davis at a Louis Armstrong nightclub appearance, and hearing Davis tell his manager: “Shut up! I want to hear Pops!”

Yet even having known Mr. Morgenstern for so many years, “Living With Jazz” came as a splendid surprise. I was too young to have read his work when he was an editor and regular contributor to Downbeat magazine, so I knew his writing mostly from liner notes. The nearly 700 pages of this book are the product of a lifetime of thinking and writing about jazz, and all contain fascinating new information and new observations.

Mr. Morgenstern is strongest on the giants of black swing – Coleman Hawkins, Roy Eldridge, Lester Young – and especially good on the development of early jazz record labels like Commodore, Keynote, and Blue Note. Yet it is also a delight to read about the beboppers and other modernists. His early impressions of Ornette Coleman and Bill Evans, for instance, turned out to be prescient. His work on Armstrong and Ellington is, as expected, brilliant. But one essay that caught me by surprise was an obituary for Charles Mingus – the best short piece I’ve read about the bassist and composer.

“Whatever Mingus did, he did with conviction and courage.” Mr. Morgenstern wrote. “In a world of codes, charades and compromises, he refused to play by the rules for which he had contempt. Always ready to strike the first blow, he left himself wide open in the process. It was this openness – to experience, to emotion, to action, to risk – that made Mingus and his music such intense and involving forces.”

Reading “Living With Jazz” is like discovering an amazing, unknown recording by one of your favorite musicians. Thumbing through “Weather Bird,” on the other hand, is like listening to some of your old favorites – and being astonished as you still hear new things.

When Mr. Giddins retired his Weather Bird jazz column from the Village Voice last December, he was unquestionably the most valuable reviewer-critic then regularly covering the jazz scene. For future generations, he will loom as the most imposing of all jazz writers, surpassing even his own inspirations, Whitney Balliett and the late Martin Williams. Williams was strongest on pure concepts, and Mr. Balliett is hard to beat in terms of the beauty of his prose. But no one puts it together like Mr. Giddins, whose writing is an unmatched combination of big ideas, witty wordsmithery, historical insight, and musicological know-how.

Mr. Giddins has set the bar for jazz scholarship so high no one is likely to top it. All the major writers of his generation – Bob Blumenthal, Stanley Crouch, Francis Davis, Peter Keepnews – would join the chorus on this point. And writers like I and the New York Times’s Ben Ratliff taught ourselves to listen to, think about, and write about jazz by studying his columns. Mr. Giddins told me 20 years ago that the closest thing he had to a secret formula for success was to “Listen to everything, read everything.” That inclusiveness is the governing factor of his authority.

Before the 1960s, most of the music press picked one side of the fence and stayed there: You were either a dirty bopper or a Dixieland moldy fig. Mr. Giddins was among the first to give equal time to the entire spectrum of jazz and related musics, from New Orleans to the New Thing, from Bunk to Monk. The great thing about the Weather Bird column – titled after the famous Louis Armstrong-Earl Hines duet – was that you never knew whether he’d cover a reissue of some prehistoric pioneer or the latest offering of some newcomer so avantgarde you hadn’t even heard of him.

Mr. Giddins is currently working on the second volume of his epic biography of Bing Crosby, writes regularly for Jazz Times and Tracks, and even reviews DVDs for this very paper. Still, his jazz column was a thing to be treasured – as is this collection. I can imagine even now the graffiti on subway walls in the vicinity of the Village Vanguard: “Weather Bird Lives!”