Anita Engle 
The Nili Spies [PDF ebook] 

An extraordinary tale, much-neglected by historians, of courage, bravery and eventual tragedy which took place during the First World War in the Middle East. It is the story of a small group of people, of whom Sarah and Aaron Aaronsohn were the core, who were devoted to the Yishuv, the Jewish community in Palestine, and who were convinced that it was in imminent danger of extinction from the Turks.They resolved to help the British in Egypt by collecting military intelligence. Unfortunately, as Peter Calvocoressi points out, their understanding of the British position was quite wrong…[their] miscalculations created the tragedy which this book recounts…”