Michael Feinstein’s got rhythm, he’s got music, and now he has a dandy new book called “The Gershwins and Me,” about Ira Gershwin and other veteran songwriters he has known.

The book’s informality is fun. It’s a long book, and very heavy, with a lot of full-color pictures. There are things Feinstein found out while hanging around with Ira and with other old Tin Pan Alley types. You can view notebooks, manuscripts, sketches and old photos. They’re fascinating.

It’s also fun to hear Feinstein dishing up affectionate anecdotes.

The stories dealing with Ira Gershwin and his wife, Lee, are funny and human. “I remember Ira asking me what was wrong one time when I must have seemed down. I said, ‘Ah, I said such-and-such to Lee and she gave me a withering look.’ He said, ‘My wife gives everybody withering looks; why should that bother you?”

Feinstein enchantingly describes what Ira’s work habits used to be like.

Before he began working on a song, Ira would sharpen his brain by doing crossword puzzles and reading arcane books about words. And then he would dive in ... but in his own way. Ira was a world-class procrastinator. When he had to write something he would put it off and put it off. He’d finally start, probably late in the day, then he’d stop to have a sandwich and read the newspaper. Finally, he’d force himself to get down to business and work for a half hour or so, and maybe he’d come up with a couple of good rhymes, and that would give him cause to celebrate. So he’d stop and have a cigar. Sometimes he would work all night like that.

We wander through the history of individual songs. For instance “I’ve Got A Crush On You,” which we now know as a sultry ballad, began life as an uptempo dance number cut from “An American in Paris.” I also had not known that the word “crush” had just come to mean infatuation. There is a slang term that has stuck.

Feinstein admits that he is free with his opinions. But I admire his opinions, because I admire him as a performer as well as a chronicler.

He amusingly blasts rock music. He holds various singers up for evaluation, and not everyone cuts it.

“Too often singers are faking it,” he writes. “They’ll seek gravitas in the words when it isn’t there and try to bring it to their performance, as if closing your eyes and emoting histrionically made a banal song more meaningful. They’ll sing it faster, or in a different key, or they’ll change harmonies, a melody or even some of the words.”

Speaking of which: “Another pet peeve of mine comes when singers close their eyes when performing, thus disconnecting themselves from the very people they’re supposed to be singing to.”

It’s funny to think that Feinstein, as impressive as his knowledge may be of the Great American Songbook, has nothing on his dad, Edward. “My dad is still the one I call when I need to know a lyric, and he still charms the ladies when he bursts into song,” Feinstein writes. He continues in parentheses: “After he met the famously acerbic actress Elaine Stritch, Elaine called to tell me how much she enjoyed meeting my father. When I responded that my mother was sorry not to have met her as well, there was a pregnant pause and she replied, ‘Damn, I was hoping she was dead.’ ”

The stories about George Gershwin, numerous as they are, are the least appealing. Feinstein didn’t know him, and that territory had already been pretty well covered. As recently as last year, an interesting book about Gershwin came out, the bittersweet memoir by Katharine Weber, called “The Memory of All That.” She was Kay Swift’s granddaughter and told the story of Swift’s long affair with Gershwin.

Speaking of that affair, I have come to an unhappy conclusion about George Gershwin: I do not really like reading about him. I love his songs, and I am sorry he died young, but he comes across as an unattractive personality – a big ego, a user, someone who obliviously hurt other people’s feelings without remorse. He seems to have put all his emotion into his music and not into much else.

It seems revealing that in a self-portrait (of course Gershwin drew himself) while he really captures himself, he draws his eyes as X’s, as if he has no heart. Anecdotes about him often leave an icky aftertaste.

Still, revolving around him were a host of other, more likable people. Oscar Levant, for instance, always makes great copy. Levant spent so much time at Ira and George’s adjoining penthouses that, Feinstein writes, he was more like a lodger than a guest. “Levant wrote the place ‘was mostly filled with an element of parasites, both aesthetic and gustatory ... Here I discovered I was a born leader, for I soon took charge of this hitherto disorganized group.”

The book’s informal nature allows Feinstein to proselytize too much sometimes about Gershwin. I am not sure that Gershwin’s songs are universally considered above everyone else’s. Get up to the level of Jerome Kern, or Cole Porter, and it’s a matter of taste.

Feinstein enjoys re-airing a few isolated rumors that Gershwin was gay. The people who uttered them to begin with were conveniently silent after that, declining to say how they supposedly knew. Who needs people like that, and who needs to have their nonsense repeated?

All in all, though, this is an enjoyable ramble through the Great American Songbook’s history, a world that Feinstein knows as few other people do. Perhaps he is even adding to it.

Discussing singers and their interpretations, he writes: “If ever I’m lucky enough to have people do cover versions of songs I’ve written, I’ll be thrilled – even if they stink.”

The Gershwins and Me:

A Personal History in 12 Songs

By Michael Feinstein

Simon and Schuster

351 pages, $45

News Classical Music Critic Mary Kunz Goldman is working on a biography of pianist Leonard Pennario.