Complex sentence: Merrill's follow-up to "Helen Merrill" was the 1956 LP, "Dream of You", which was produced and arranged by bebop arranger and pianist Gil Evans, whose work on "Dream of You" was his first in many years.
Split into simpler sentences: Merrill's follow-up to "Helen Merrill" was the 1956 LP, "Dream of You", which was produced and arranged by bebop arranger and pianist Gil Evans. Evans' work on "Dream of You" was his first in many years.