A musical work might be known by many different titles (see box).
A uniform title (or preferred title) is the version of a title standardized by catalogers. Books, scores, and recordings of a particular musical work can be searched more quickly by searching by uniform title.
Uniform titles can also be used to show groups of pieces put together in a published work (like 3 sonatas in one volume). Like this:
Quartets, strings
Chamber music. Selections
Works
That last one is important. If we have a complete works edition of a given composer, you'll find it listed under "Works." The same would be used for an edition of CDs of every single work by a given composer.
Uniform titles come in two flavors:
Distinctive titles are titles that are unique--for example, there's only one Firebird by Stravinsky. However, the title appears in its original language. So for example, Firebird appears as Zhar-ptitsa:
Stravinsky, Igor, 1882-1971. Zhar-ptitsa
Mozart, Wolfgang Amadeus, 1756-1791. Nozze di Figaro
Orff, Carl, 1895-1982. Carmina Burana
Corigliano, John, 1938-. Fern Hill
Form titles use the common genre names familiar to most musicians--particularly with instrumental music--like Sonatas, Masses, Quartets, etc.
Form titles have several common bits:
Here are a couple of examples:
Beethoven, Ludwig van, 1770-1827. Quartets, violins (2), viola, cello, no. 16, op. 135, F major
Bach, Johann Sebastian, 1685-1750. Masses, BWV 232, B minor
"Extra Information" can be used for a variety of useful bits of information. For example:
Purcell, Henry, 1659-1695. Fairy queen. Vocal score
Palestrina, Giovanni Pierluigi da, 1525?-1594. Masses, book 3. Missa brevis
Orff, Carl, 1895-1982. Carmina Burana. Libretto. English and Latin
These are all titles of scores, recordings, and the like related to Beethoven's Moonlight sonata. Clearly, you'd have a hard time finding them all, right?
A night in Vienna
Adagio from the "Moonlight sonata" : op. 27, no. 2
Adagio sostenuto from the Sonata, op. 27, no. II : moonlight
Beethoven's "Moonlight sonata"
Chiaro di luna : I. tempo della Sonata op. 27 no. 2
First movement of the Sonata quasi una fantasia (Moonlight sonata) : op. 27, no. 2
Klaviersonate cis-Moll op. 27 Nr. 2 : "Mondschein-Sonate"
Klaviersonate Op. 27/2 = Piano sonata op. 27/2 : Sonata quasi una fantasia
Moonlight sonata : Sonata quasi una fantasia, op. 27, no. 2
Sonata quasi una Fantasia "Mondschein" op. 27 no. 2
Sonata quasi una Fantasia, Op. 27, No. 2
Sonata, for the piano forte
Sonata, op. 27, no. 2 in C # minor : (moonlight)
Theme from the First movement of Beethoven's Moonlight sonata : piano, four hands : simplified version
Zongoraszonata
Beethoven, piano music inspired by women in his life
Nocturne : a selection of the most beautiful piano music for dreaming
Piano compositions
Sonatas : for piano
Zwei Sonaten, für Klavier
Moonlight sonata : handbells 5 octaves
My song for you : based upon Beethoven's Moonlight sonata : vocal-dance orchestration
Veränderung der Sonate für Klavier op. 27,2 von Ludwig van Beethoven : in Sonate für Horn und Klavier op. 95
That's why uniform titles are so handy--you can just search for the uniform title and you (should) get all of these.
Sonatas, piano, no. 14, op. 27, no. 2, C# minor