The poems in both books cover the themes of romance, drugs & alcohol, supernatural beings, angst and religion. I believe Indigo Glow was released prior to The Tree Outside My Window, but I actually read both at the same time, leaving each book in a different room to dip in to when I fancied a read.
To me, The Adversary’s Good News is a much more mature piece of writing. I feel that anyone could enjoy it and gain from it. These poetry collections are perhaps a little more niche. I would recommend them to teenagers and twenty-somethings, or those still struggling with the general themes of life, looking for others to relate to.