Scriabin's Prelude Op. 39 No. 1 is a deeply atmospheric and harmonically rich work, characteristic of his mature style. It unfolds with a searching, often melancholic, melodic line supported by lush, impressionistic harmonies.
Mastering the complex harmonic language and achieving a sensitive rubato are key challenges.
4 Preludes (Op.39) is rated Henle level 7 of 9 — late advanced repertoire, roughly ABRSM grade 8 and above. In the RCM system it corresponds to about level 9.
You should be comfortable at Henle level 7 — meaning you can already play level 6–7 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of 4 Preludes (Op.39) lasts about 3 minutes.
4 Preludes (Op.39) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.