Transcriptions play a very important role in the repertoire for classical guitar because, as an instrument, the guitar has some awkward gaps in its historical repertoire. In very broad strokes, music for instrumental soloists and ensembles didn't really become important until early in the 16th century. Publishers like Ottaviano Petrucci were among the first to issue sheet music from movable type. Before then, music was disseminated through manuscript copies. From Wikipedia:
A total of 61 music publications by Petrucci are known. By far the most fruitful period of his life for publishing music was the period between 1501 and 1509, during which he published the three volumes of chansons (the Odhecaton being the first), 16 books of masses, five books of motets, 11 anthologies of frottole and six books of music for lute.You can see that, after vocal music, the most important genre was music for lute, the premiere domestic instrument. The music for lute usually comprised either transcriptions of vocal polyphony or pieces in that style, or instrumental dances. One early exception were the sets of variations we find in the books for vihuela, the Spanish cousin to the lute. The lute dominated solo instrumental music until the harpsichord took over in the later 17th century. The five-course Baroque guitar enjoyed a flurry of interest in the late 17th and early 18th century, but the writing was on the wall: from then on keyboard instruments were completely dominant. The late 18th century composers of music for guitar like Fernando Sor and Mauro Giuliani were completely overshadowed by keyboard composers like Haydn, Mozart and Beethoven. The guitar hung on by a thread in the 19th century, but by the end it was relegated to mere local color in the music of Francisco Tárrega. I don't mean to slight his fine compositions, but they are not even close to being in the same league as the great 19th century keyboard composers such as Frederic Chopin, Franz Liszt or Robert Schumann. Largely through the efforts of players like Agustín Barrios, Miguel Llobet and Andrés Segovia, the guitar enjoyed a renaissance in the 20th century that saw outstanding compositions from the pen of composers such as Benjamin Britten, Eliot Carter, Steve Reich and many, many others.
But artists like Segovia, in their quest to put the guitar back on the concert stage, encountered some real problems with the repertoire. Apart from a scattering of works by Sor, Giuliani and Tárrega, the only repertoire was being created from scratch by composers like Moreno-Torroba and Ponce who were working directly with Segovia. So he started investigating how the repertoire could be substantially augmented through transcription. The implication of the term "transcription" as opposed to "arrangement" is that the transcription is a version faithful to the original and one that can stand in for the original in a concert performance. An arrangement is often a considerably altered version suitable for particular circumstances.
The big holes in the guitar repertoire were in the Baroque and Romantic eras, so that is where Segovia concentrated. He found excellent potential in the music of the Spanish nationalist composers like Isaac Albéniz and Enrique Granados whose piano music so evokes that guitar that, if you can manage to fit the notes on the instrument, it sounds entirely natural. These transcriptions have been so successful that pieces like Asturias (Leyenda) by Albéniz are probably played on guitar more often than they are on piano. Another composer who saw his music transcribed for guitar was Chopin, though the effort was not as successful (there is an excellent version of one of the nocturnes by Tárrega). Liszt was not feasible, though a few of the shorter pieces by Schumann have appeared.
The big prize, as far as Segovia was concerned, was Bach. If he could only find some music by J. S. Bach that could be added to the guitar repertoire that would go a long way to proving the instrument's suitability as a major solo instrument. It was here that he really struck gold. One of his most inspired ideas was to transcribe the enormous Chaconne that forms the last movement of the Partita No. 2 in D minor for solo violin. This, and the other suites for solo violin, are so contrapuntally rich that they are ideal for performance on guitar. Indeed, except for a few added bass notes, Segovia had no work to do in transferring the Chaconne to guitar. It was and is a huge part of the repertoire. Other pieces that proved successful were the Siciliana from the Sonata No. 1 and all of the Partita No. 3 in E major, which Bach himself did a version of for Baroque lute with added basses.
Bach was important because he was the only one of the truly major composers that could easily be included in the guitar repertoire. Transcriptions were attempted of pieces by Haydn, Mozart and Beethoven, but none of them proved very successful. The only other Baroque keyboard composer who has seen a lot of performance on guitar is Domenico Scarlatti whose 555 sonatas for harpsichord were many of them inspired by guitar timbres and textures. Perhaps ten or twelve of them are often heard in guitar concerts.
Another area that is very suitable for transcription is the enormous quantities of music for lute and vihuela, most of which transfers over to guitar with one minor change in tuning. You can even play directly from the original tablature if you want. (Until the 18th century, all music for lute and vihuela was published in tablature.) This is not true of the music for Baroque lute, which uses a different tuning entirely.
In recent years the growth of the Early Music movement and the subsequent appearance of many performers on the lute and vihuela has meant that we are losing a lot of this repertoire back to the original instruments.
Now for the list:
1. Chaconne from the Partita No. 2 in D minor by J. S. Bach. Originally for solo violin. There are innumerable recordings on guitar but the version by Segovia remains a benchmark:
2. Fugue (and Siciliana) from the Sonata No. 1 by J. S. Bach. Originally for solo violin. Ana Vidovic has a quite brisk performance of the fugue:
3. Partita No. 3 in E major (in the version for lute) by J. S. Bach. Originally for solo violin. The guitarist who really put this piece on the map for guitarists was John Williams whose integral version of the lute suites (this is the Lute Suite No. 4) was a revelation. This is the prelude:
4. Suite in D major by J. S. Bach. Originally for solo cello. I called this the "Suite in D major," but it is often referred to just as the "First Cello Suite" because that's what it is! It is usually played in D major due to an early transcription by John Duarte (that Williams recorded). When I played it for José Tomas in Spain when I was studying with him he picked up his eight-string guitar, dug out the cello music and sight read through the prelude. He suggested doing it in A major instead of D to keep it close to the original G major key. Then you wouldn't be tempted to add gratuitous bass notes. Decades later I got around to it and have recorded the whole suite in A major. I think it works quite well. Here is the prelude:
5. Sonatas by Domenico Scarlatti: K. 322 and 208. Originally for harpsichord. Out of a host of possibilities I pick these two which are especially popular. Here is Scott Tennant with K. 322:
And here is Leo Brouwer with K. 208:
6. Asturias (Leyenda) by Isaac Albéniz. Originally for solo piano. Again, simply everyone has recorded this piece, which sounds absolutely natural on guitar. Everyone includes me, so here is my version:
7. Granada by Isaac Albéniz. Both this and the previous piece are from his Suite Espagnola and Manuel Barrueco showed everyone how they should be played on an album devoted to Albéniz and Granados. Here is his performance. Blogger can't seem to find it, so follow the link:
8. Valses Poéticos by Enrique Granados. It was John Williams that put this piece on the map for guitarists. Other pieces often played on guitar include Granados' Danzas Españolas. Here is Williams with the Valses Poéticos. He did two transcriptions, the first one of just some of the walzes, the second with all. This is the second version. Again, follow the link.
9. Estudio Brillante by Alard (transcribed/arranged by Tárrega). This is a bit of a surprising choice because it is not a piece played a lot, but I think it is a very successful transcription (or arrangement, I have never seen the original) by Tárrega of a piece originally for violin by Alard. Christopher Parkening does an excellent performance:
10. Suite Española by Gaspar Sanz arranged for guitar by Narciso Yepes. This is standing in for a host of transcriptions of music for Baroque guitar. Here is the last movement, Canarios, played by Yepes:
Of course I could have made a lot of different choices. For one thing, I completely missed out all the Renaissance lute music, but you can play that on guitar without actually doing any transcribing! Just tune your third string to F#.