This World: Playground or Battleground? by A W Tozer and published by Classics.
In this book Tozer calls us to consider carefully the seriousness of the spiritual struggle we are all engaged in. There was a time, Tozer writes, when our Christian forebears saw the world as it truly is: a battlefield. They knew that hell was a force pitted against God, heaven and righteousness.
Tozer fears that now people think of the world as a playground, not a battleground. He exhorts us to realise the crucial seriousness of the spiritual struggle we are all engaged in, but to also to remember and grasp it is a battle in which victory is certain.