Excerpts from Books and Wikipedia
"Begin’s most significant achievement as Prime Minister was the signing of a peace treaty with Egypt in 1979, for which he and Anwar Sadat shared the Nobel Prize for Peace. In the wake of the Camp David Accords, the Israel Defense Forces (IDF) withdrew from the Sinai Peninsula, which was captured from Egypt in the Six-Day War. Later, Begin’s government promoted the construction of Israeli settlements in the West Bank and the Gaza Strip. Begin authorized the bombing of the Osirak nuclear plant in Iraq and the invasion of Lebanon in 1982 to fight PLO strongholds there, igniting the 1982 Lebanon War. As Israeli military involvement in Lebanon deepened, and the Sabra and Shatila massacre, carried out by Christian Phalangist militia allies of the Israelis, shocked world public opinion, Begin grew increasingly isolated. As IDF forces remained mired in Lebanon and the economy suffered from hyperinflation, the public pressure on Begin mounted. Depressed by the death of his wife Aliza in November 1982, he gradually withdrew from public life, until his resignation in October 1983." [Wikipedia]