The Yom Kippur War, also known as the Ramadan War, the October War, the 1973 ArabIsraeli War, or the Fourth ArabIsraeli War, was an armed conflict fought from 6 to 25 October 1973 between Israel and a coalition of Arab states led by Egypt and Syria. The majority of combat between the two sides took place in the Sinai Peninsula and the Golan Heightsboth of which were occupied by Israel in 1967with some fighting in African Egypt and northern Israel. Egypt's initial objective in the war was to seize a foothold on the eastern bank of the Suez Canal and subsequently leverage these gains to negotiate the return of the rest of the Israeli-occupied Sinai Peninsula.The war began on 6 October 1973, when the Arab coalition jointly launched a surprise attack against Israel on the Jewish holy day of Yom Kippur, which had occurred during the 10th of the Islamic holy month of Ramadan in that year; Egyptian and Syrian forces crossed their corresponding ceasefire lines with Israel and invaded the Sinai Peninsula and the Golan Heights, respectively. Following the outbreak of hostilities, both the United States and the Soviet Union initiated massive resupply efforts to their respective allies during the war, which led to a near-confrontation between the two nuclear-armed superpowers.Fighting commenced with a massive and successful crossing of the Suez Canal by the Arab coalition; Egyptian forces crossed the ceasefire lines with Israel and advanced virtually unopposed into the Sinai Peninsula. However, Israel mobilized most of its forces three days later and halted the Egyptian offensive, resulting in a military stalemate. The Syrians coordinated their attack on the Golan Heights to coincide with the Egyptian offensive and initially made threatening gains into Israeli-held territory. After three days of heavy fighting, Israeli forces had pushed the Syrians back to the pre-war ceasefire lines. The Israeli military then launched a four-day-long counter-offensive deep into Syria. Within a week, Israeli artillery began to shell the outskirts of the Syrian capital of Damascus, and Egyptian president Anwar Sadat began to worry about the deteriorating integrity of the Arab coalition's leadership. Sadat believed that capturing two strategic mountain passes deeper within the Sinai Peninsula would make the Arab position stronger during post-war negotiations with Israel, and subsequently ordered Egyptian forces to mount another offensive against the Israelis, which was quickly repulsed. Israeli forces subsequently counter-attacked at the seam between the two Egyptian formations, crossed the Suez Canal into Egypt, and slowly began advancing southward and westward towards Suez City in over a week of heavy fighting that resulted in large casualties on both sides.On 22 October, an initial ceasefire brokered by the United Nations unravelled, with each side blaming the other for the breach. By 24 October, the Israelis had improved their positions considerably and completed their encirclement of the Egyptian Third Army and Suez City, bringing them within 100 kilometres (62 mi) of the Egyptian capital of Cairo. This development led to dangerously heightened tensions between the United States and the Soviet Union (allied with Israel and with the Arab states, respectively) and a second ceasefire was imposed cooperatively on 25 October to officially end the war.

The Yom Kippur War had far-reaching implications; the Arab world had experienced humiliation in the lopsided rout of the EgyptianSyrianJordanian alliance in 1967, but felt psychologically vindicated by early successes in the 1973 conflict. The Israelis recognized that, despite impressive operational and tactical achievements on the battlefield, there was no guarantee that they would always dominate the Arab states militarily, as they had done consistently throughout the First ArabIsraeli War, the Second ArabIsraeli War and the Third ArabIsraeli War; these changes paved the way for the IsraeliPalestinian peace process. The 1978 Camp David Accords that followed the war saw Israel return the entire Sinai Peninsula to Egypt and the subsequent 1979 EgyptianIsraeli peace treaty, which marked the first instance of an Arab country recognizing Israel as a legitimate state. Following the achievement of peace with Israel, Egypt continued its drift away from the Soviet Union and eventually left the Soviet sphere of influence entirely.

Israel (; Hebrew: יִשְׂרָאֵל, romanized: Yīsrāʾēl; Arabic: إِسْرَائِيل, romanized: ʾIsrāʾīl), officially the State of Israel (מְדִינַת יִשְׂרָאֵל, Medīnat Yīsrāʾēl; دَوْلَة إِسْرَائِيل, Dawlat ʾIsrāʾīl), is a country in Western Asia. It is situated on the southeastern shore of the Mediterranean Sea and the northern shore of the Red Sea, and shares borders with Lebanon to the north, Syria to the northeast, Jordan to the east, and Egypt to the southwest; it is also bordered by the Palestinian territories of the West Bank and the Gaza Strip to the east and west, respectively. Tel Aviv is the economic and technological center of the country, while its seat of government is in its proclaimed capital of Jerusalem, although Israeli sovereignty over East Jerusalem is unrecognized internationally.Israel has evidence of the earliest hominid migrations out of Africa. Canaanite tribes are archaeologically attested in the region since the Middle Bronze Age, while the kingdoms of Israel and Judah emerged during the Iron Age. The northern Kingdom of Israel was destroyed by the Neo-Assyrian Empire around 720 BCE, and the Kingdom of Judah was incorporated into the Neo-Babylonian Empire in 586 BCE. Some of the Judean population was exiled to Babylon, only to return after Cyrus the Great conquered the region. The Maccabean Revolt against Seleucid rule led to an independent Hasmonean kingdom by 110 BCE. The kingdom became a client state of the Roman Republic in 63 BCE, following which the Herodian dynasty was installed by 37 BCE, and in 6 CE, the former kingdom was finally incorporated into the Roman Empire as the province of Judaea (Latin: Iudaea). A series of unsuccessful Jewish revolts against the Romans that broke out during the first and second centuries resulted in the destruction of Jerusalem, the expulsion of many Jews, and the renaming of Iudaea to Syria Palaestina. In the 7th century CE, the Byzantine-ruled Levant was taken by Arab forces and incorporated into the Rashidun Caliphate. It remained in Muslim hands until the First Crusade of 1096–1099 re-established a Christian sovereign presence; Crusader control was partly dismantled by the Ayyubids in 1187, but ultimately lasted until 1291. The Mamluk Sultanate of Egypt extended its control over the region by the end of the 13th century until its defeat in 1516 to the Ottoman Empire. During the 19th century, a national awakening among Jews led to the founding of Zionism, a movement that espouses the return of a Jewish homeland in Palestine, also known as the Land of Israel, which was followed by the immigration of diaspora Jews.

Following World War I, Britain controlled the entirety of the territory of what makes up Israel, the Palestinian territories, and Jordan as a League of Nations mandate. After World War II, the newly formed United Nations adopted the Partition Plan for Palestine in 1947, recommending the creation of independent Arab and Jewish states, and an internationalized Jerusalem. The plan was accepted by the Jewish Agency but rejected by Arab leaders. Following a civil war within Mandatory Palestine between Yishuv and Palestinian Arab forces, Israel declared independence at the termination of the British Mandate. The war internationalized into the 1948 Arab–Israeli War between Israel and several surrounding Arab states and concluded with the 1949 Armistice Agreements that saw Israel in control of most of the former mandate territory, while the West Bank and Gaza were held by Jordan and Egypt respectively. Israel has since fought several wars with Arab countries, and since the Six-Day War in June 1967 has occupied several territories, and continues to occupy the Golan Heights and the Palestinian territories of the West Bank, including East Jerusalem, and the Gaza Strip, though whether Gaza remains occupied following the Israeli disengagement is disputed. Israel has effectively annexed East Jerusalem and the Golan Heights, though these actions have been rejected as illegal by the international community, and established settlements within the occupied territories, which the international community also considers illegal under international law. Efforts to resolve the Israeli–Palestinian conflict have not resulted in a final peace agreement, while Israel has signed peace treaties with both Egypt and Jordan, and more recently has normalized relations with a number of other Arab countries.

In its Basic Laws, Israel defines itself as a Jewish and democratic state, and as the nation-state of the Jewish people. The country is a liberal democracy with a parliamentary system, proportional representation, and universal suffrage. The prime minister serves as head of government and the Knesset is the unicameral legislature. Israel is a developed country and an OECD member, and has a population of over 9 million people as of 2021. It has the world's 31st-largest economy by nominal GDP, and is the most developed country that is currently in conflict. The standard of living in Israel is the highest in the Middle East, and the country ranks high on the global HDI list. Israel also ranks among the world's top countries by percentage of citizens with military training, percentage of citizens holding a tertiary education degree, research and development spending by GDP percentage, women's safety, life expectancy, innovativeness, and happiness.