The two noctures of Op. 55 were Frédéric Chopin's penultimate group of nocturnes (only the Op. 67 pair were composed at a later date; all the posthumously published nocturnes actually came from the composer's younger days). The two pieces have had a turbulent and often unhappy history. While most musicians of the late twentieth century regarded them as two of the finest entries in the genre, during much of the nineteenth and early twentieth centuries, the pair was ignored by the majority of concertizing pianists. Certainly it is easy to understand the professional neglect heaped on the Nocturne in F minor, Op. 55/1, which, due to its relative technical ease, has become the property of amateurs and students around the globe. The E flat Nocturne, Op. 55/2, however, is a work of extraordinary power and a testament to both the masterly command of Chopin's later years and the distance he had traveled since the Fieldian nocturnes of his Op. 9.
The primary melody of the Nocturne in F minor, Op. 55/ 1, has a bittersweet tang. The piece as a whole is cast in the characteristic (ABA) ternary form, with a dramatic and anxious middle section. An exciting stretto passage leads directly into the reprise of the opening theme, which has itself assimilated something of the second subject's agitation. A welcome harmonic change (from the minor to the major mode) as the coda progresses, and a trio of arpeggiated chords make a firm conclusion. This nocturne, though clearly less inspired than some of its brothers and sisters, makes an effective entry-level piece for those players and listeners seeking a clear glimpse of the composer's basic style.
The Nocturne in E flat major, Op. 55/2, however, is a different matter altogether. Few pieces are less suitable for such an instructive purpose as that described above, and yet few are so eminently rewarding as a musical experience. Here there is no discrete sectional form, but rather a continuously developing melodic strand. If this causes a certain monotony, then it is the same brand of monotony that one's own inner stream of consciousness can, at times, engender. It is as if the composer has abandoned all the external trappings of nocturne "form" in order to place a greater emphasis on the essence of the genre's sentiment. The interested student of Chopin would do well to make a careful comparison of this work with the more famous E flat Nocturne, Op. 9/2: the contrast is striking, and the greater skill of the later work cannot be overstated. A worthy coda (containing, around 12 bars from the end, a modulation of the finest and most expressive kind) serves as a conclusion to this unique work.