Ever since Gloria Estefan split from Miami Sound Machine in 1989 to go solo, her best efforts tended to be her Spanish-language ones, and her fourth such album, 90 Millas, is no exception.

In fact, it might be her best overall effort -- regardless of language -- since Mi Tierra (1993), which was her first to be sung entirely in Spanish and an instant, best-selling classic.

In a couple ways, 90 Millas is a follow-up to Mi Tierra.

Both are heartfelt albums inspired by Cuba and Cuban music -- whereas Abriendo Puertas (1995) and Alma Caribeña (2000), Estefan's other two prior Spanish-language efforts, were more broadly Hispanic and Caribbean, respectively, in their influences and intent -- and both 90 Millas and Mi Tierra are graced by some of Latin music's most gifted instrumentalists, many of them legends.

In this case, the featured guests include Papo Lucca, Johnny Pacheco, Candido Camero, Paquito d'Rivera, Nelson González, Andy García, Sheila E, Carlos Santana, Orestes Vilato, Israel "Cachao" López, Generoso Jiménez, Giovanni Hidalgo, India, José Feliciano, Arturo Sandoval, Sal Cuevas, and Luis Enrique.

It's an impressive lineup of musicians; for instance, the album's lead single, "No Llores," alone boasts Carlos Santana on electric guitar, José Feliciano on acoustic guitar, Sal Cuevas on bass, Sheila E. on timbales, and Luis Enrique on congos and bongos.

That's not all, though.

90 Millas also boasts an ace production and songwriting team: husband/impresario Emilio Estefan (of course) and the Gaitán Bros. (Ricardo and Alberto).

Then there's Gloria herself, who is the vehicle for this superstar project.

She's in good voice here -- as well-mannered and graceful as usual -- and co-writes many of the songs.

Yet it's the musicianship and the songs themselves, surprisingly few of them ballads, that shine brightest here on this love letter to Cuba, that oft-romanticized, and fiercely politicized, island 90 miles off the coast of Florida.

Though born there, Gloria left as a child.

In her heart, however, she never left her homeland behind, as this album and its predecessor, Mi Tierra, make clear, for both albums are among the best -- and certainly most poetic and impassioned -- efforts of her long, illustrious career.

Practically every song here is a gem, and they're a rarity in 2007, a year in which traditional Cuban music like this couldn't have been further away from the mainstream of Latin music in America, where regional Mexican and urban dominated the marketplace.