One definition of strategy is 'the art and science of developing and employing instruments of national power in a synchronised and integrated fashion to achieve theatre, national and/or multinational objectives.'
In this article from The Strategy Bridge Chris reviews The Direction of War: Contemporary Strategy in Historical Perspective and Strategy: Context and Adaptation from Archidamus to Airpower and explains how they support this definition. He believes that these two books are valuable contemporary sources of practical examples and ideas for how civilian and military leaders, at all levels, work to harmonise policy, strategy and operations.
The Direction of War by Hew Strachan, 2013 & Strategy by Richard Bailey, James W. Jr. Forsyth, and Mark O. Yeisley (editors), 2016.
Copies of 'The Direction of War: Contemporary Strategy in Historical Perspective' and 'Strategy: Context and Adaptation from Archidamus to Airpower' are available from the Defence Library Service (DPN only).