Sonata Arctica is a Finnish power metal band from the town of Kemi, originally assembled in 1996.The Days of Grays is the sixth full-length studio album.

The album will be released on September 16 in Finland, September 18 in Europe and September 22 in North America through Nuclear Blast. The special edition of the album will include the album along with an orchestral CD as a digipak. The orchestral versions will be slower than the album version and will include extra added piano and more calm and soft singing.

The name for the The Days of Grays apparently took a very long time to come to as the band had a name for the record that was deemed more appropriate "for a death metal band or something" according to Henrik Klingenberg. In a French interview, Tony Kakko stated that the original name was Deathaura, the name of a song on the album. However, when lead singer Tony Kakko was playing World of Warcraft with some of his friends, a friend of the band suggested the name, the rest of the band liked. This name became the album's official name