In the year of Leo Records' fortieth anniversary, it seems fitting to spotlight one of the label's most recorded players, the Brazilian-born, New York-based saxophonist Ivo Perelman, whose sixty-plus Leo releases dwarf the numbers by such supposed Leo regulars as Anthony Braxton, Jöelle Léandre or Sun Ra. Perelman is notorious for his large-scale projects such as the six volumes of The Art of the Improv Trio series, the seven of The Art of Perelman-Shipp, or the four of Strings, recorded with members of the violin family. His latest project might be just as voluminous as those series, if he can find musicians to record with; its aim is to record a series of duets with improvising bass clarinet specialists — not those who double on the instrument — and they are not plentiful. Kindred Spirits is the first release in this new series. A double CD, it features Perelman in a duo with the German Rudi Mahall who unquestionably fits the description 'bass clarinet specialist', but probably deserves the title 'master' instead of 'specialist'. (Incidentally, the release of the second in the series, Spiritual Prayers, with Chicago's Jason Stein on bass clarinet, was not far behind.)

In June 2018, Perelman and Mahall — having never met or played together before — recorded together at Parkwest studios, Brooklyn, freely improvising twelve tracks, ranging in length from two-and-a-half to almost thirteen minutes, altogether one-hundred minutes of music. The only sounds heard on the album are tenor sax and bass clarinet. Right from the start, it is obvious why Perelman decided on this series; the two instruments sound perfect together, having ranges and timbres that complement one another while keeping them distinguishable. To add any other instrument alongside them would have risked marring that perfection.

After the recording, Perelman was reportedly delighted and amazed at the instant rapport he and Mahall had with one another, and awestruck by the resulting music. Yes, the album's title is very fitting. That rapport which so pleased Perelman meant that the two clicked immediately, displaying an uncanny understanding of each other's playing styles and instincts, and an ability to anticipate where the other one would go next. At times, this can give the impression that the two were not freely improvising but following some pre-arranged score, printed or otherwise. Most of the time, they follow paths that differ slightly but interweave and harmonise together, each reacting to and commenting upon the other. Throughout, neither one is leading or accompanying the other; they are going forward together, perfectly in step, without tripping over each other. A marvel of duo improvisation.