1. Allegro moderato
2. Lento assai
3. Scherzo. Allegro ma non troppo
4. Allegro non troppo

De'ak summarizes this work on pages 271-272 of his book:

Concerto (Op. 72) in B minor ... was published in 1900. Here he abandoned his practice of stating a long lyric theme as an opening and used, instead, a short, crisp motive which reappears in a quasi-cyclic form in the second and last movements, but not in the third, scherzo, movement. It assumes various rhythms — three-four. four-eight, and two-two. The work is well-planned and demonstrates an intention to create something new in form and treatment for both the orchestra and solo instrument. The main motive also reappears as a secondary element in the orchestra during an Andante interlude, after which a brief solo cello cadenza leads into the fourth movement. 

The technical aspects clearly foreshadow new developments in the Hohe Schule des Violoncellspiels, as can be observed in several of the studies. The B minor Concerto was a new departure, and it was seldom performed. To my knowledge, even Popper never performed it in public, though he did teach it. He preferred to play his E-minor Concerto, or the Volkmann, rather than make the exertion to introduce the B minor Concerto — although it was performed by his advanced pupils in his class. The first world war ended the chance for interest to be aroused in this concerto. Maybe someone involved in reintroducing old music will make the effort to resurrect this unique work by Popper. 

Popper made use of thematic fragments and rhythmic motives in the accompaniments, thus integrating and enriching the piano and cello combination. The solo instrument was given full harmonic support, without being dominated by the accompaniment.

First Edition: Hofmeister: vc/pf plate 8603