Ever since their days back in Boston when they met while studying with Jaki Byard, Michael Moore and Fred Hersch have always shared the stage on different projects, their most prolific encounter in the band Thirteen Ways with drummer Gerry Hemingway. This is a first recorded effort for them released in a duet format, showing a lighter, less-freely improvised side, while also tackling Latin popular/classical themes, jazz standards, not-so-standard American songs, and a small handful of originals. Moore's clarinet or alto sax speaks volumes of jazz via European historical chapters and verse, while Hersch's always poetic piano languishes in deeply thoughtful light blue hues. It is a magical union based on sheer trust, shared values, and high-level musicianship. The Latin pieces are particularly arresting, as the peaceful, pretty "Aquellos Ojos Verdes," the tango-flavored "Doce de Coco," and Hersch's gorgeous original "Canzona" stand out. You also get a bouncy children's theme set to music, profoundly saddened or chamber blues, music of Thelonious Monk, a mooing cow sound, and some free music, but not a lot. Hersch's "Lee's Dream" sounds like an "Out Of Nowhere" variation, while Moore's "Sandwiches & Brandy" could have stemmed from the standard "But Not for Me." It's the utter variety, interesting choices of material, and brave musical inventiveness without pushing the envelope that make This We Know something all lovers of jazz can universally enjoy -- anytime or anywhere.