Forgotten soldiers. We all know about Gallipoli; hopelessly conceived mess, dreamed up by Churchill to move the Great War from the glued trenches of France to a fast-moving invasion of Germany's Ottoman allies in 1915.

Embark a vast army of Australians, New Zealanders, Brits, French and others east of Istanbul in order to smash "Johnny Turk". Problem: the Turks fought back ferociously as Mustafa Kemal (later Ataturk, titan of the 20th century, etc) used his Turkish 19th Army Division to confront the invaders' first wave. Problem two: most of the division were not Turks at all.

They were Arabs. Indeed, two-thirds of the first men to push back the Anzac forces were Syrian Arabs from what is today Lebanon, Jordan, Syria and "Palestine". And of the 87,000 "Turkish" troops who died defending the Dardanelles, many were Arabs. As Palestinian Professor Salim Tamari now points out, the same applies to the Ottoman battles of Suez, Gaza and Kut al-Amara. In the hitherto unknown diary of Private Ihsan Turjman of the Ottoman Fourth Army – he would today be called a Palestinian Arab – there was nothing but scorn for those Arab delegations from Palestine and Syria who sent delegations "to salute the memory of our martyrs in this war and to visit the wounded".

What, he asked in his secretly kept diary, were these Arabs playing at? "Do they mean to strengthen the relationship between the Arab and Turkish nations... truth be told, the Palestinian and Syrian people are a cowardly and submissive lot. For if they were not so servile, they would have revolted against these Turkish barbarians," he wrote. This is stunning stuff.

Far more Arabs fought against the Allies on behalf of the Ottomans than ever joined Lawrence's Arab revolt, but here is Private Turjman expressing fury at his masters.

Year of the Locust is an odd little book, terribly short but darkly fascinating, concentrating on the Great War diaries of three Ottoman soldiers, one of them an actual Turk, the others Palestinian Arabs. We are used to British and German soldiers' accounts of the Great War; scarcely ever do we read of the personal lives of our Ottoman opponents. The Turjman family home, by extraordinary chance, is the very same Jerusalem building, in ruins since the 1967 Arab-Israeli war but now transformed into an art gallery, which I visited in Jerusalem just three weeks ago today.

In 1917, when Turjman was shot dead by an Ottoman officer, Palestinian Arabs were less concerned about the Balfour Declaration than whether the British would give them independence, annex them to Egypt or allow them a Syrian homeland. How wrong could they have been? Britain had no intention of adding to its Egyptian interests when it had already given its support to a Jewish homeland in Palestine. Later, as Tamari recounts, the lives of the other two diarists, one Turkish, the other Arab, would revolve around Palestinians who came to believe that it was Jewish immigration that would threaten their future. But it is the Great War that dominates their memoirs.

In the anti-Ottoman literature that permeated the Arab world (and the West) after the war, it is important to remember these Ottomans, Turkish or Arab. There is a touch of Robert Graves here. Turjman's diary records the plague of locusts that settled upon Jerusalem, the cholera and typhus and the 50 Jerusalem prostitutes sent to entertain Turkish officers, the Ottoman troops hanged outside the Jaffa Gate for desertion, the Turkish aircraft that crashes ("badly trained pilots or badly maintained engines"). Turjman even has a crush on a married woman.

Long forgotten now are the Arab-Turkish Ottoman inmates of the Tsarist prison camp at Krasnoyarsk, in Russia, where Lieutenant Aref Shehadeh, born in Jerusalem in 1892, ended up. Islam united them; class divided them. But there were concerts, sports clubs, football teams, a camp library, a Great War version of all the stalags and oflags made famous in the Second World War. Come the Bolshevik revolution, Shehadeh high-tailed it back to the Middle East – via Manchuria, Japan, China, India and Egypt via the Red Sea.

But the most impressive text in this tiny book is not a diary but a letter from Shehadeh's wife, Saema, in Jerusalem when, 30 years later, he had set off for Gaza as a British mandate officer. "I woke up early this morning," she writes. "I walked around in the garden for a while. I picked up some flowers and leaves. I picked up some beans to cook for myself. While I was milling around, you were always on my mind. It is your presence that makes this garden beautiful.