"Vala" or "The Four Zoas" is one of Blake's few surviving manuscripts and affords an opportunity to examine a significant evolution in his poetic practice. While the poem itself exhibits a consistent thematic interest, the modes and methods of representing these interests underwent a radical change in the ten or more years in which Blake wrote and reworked the poem. This text offers an extended and detailed treatment of the gradual shift that took place in Blake's poetics during the composition, transcription and revision of "Vala" or "The Four Zoas".