 In the same way, there will be connections between his fourth book, "Métamorphose en bord du ciel", but not to the same extent as "La mécanique du cœur".Mathias is the main songwriter and frontman.He has also written three books – "38 mini westerns" (Pimientos, 2003), "Maintenant qu'il fait tout le temps nuit sur toi" (Flammarion, 2005) et "La mécanique du cœur" (Flammarion, 2007) – with inspiration drawing between the albums and the novels.