As others have written here, this is the album that bridges Elvis v1.0 and Declan v1.0.  Whether it's the masterpiece where black and white turns to color (i.e. The Beatles' Revolver) is often debated.  For my money, this is the best that Elvis/Dec would do for at least the next 15 years - his subsequent work, IMHO, being dabblings in this genre or that.