Allah is the proper name applied to the only true God Who exists necessarily by Himself, comprising all the excellent Divine names and attributes of perfection. Allah is One and Unique; He has no partner or equal. He is the sole Creator and sustainer of the universe. Every creature bears witness to His Oneness. Divinity, Lordship and the uniqueness of His attributes and names. Allah's essence does not resemble other essences; "There is none like unto Him". He is the One, the Sole, the Indivisible. He is the God without Whom no affairs are accomplished, and to Whom Lordship ultimately pertains. He neither begets nor is begotten. He does not inhere in anything, nor does anything inhere in Him. All creatures stand in need of Him, but He stands in need of none.
Allah is the Omnipotent, the Omniscient, Whose knowledge comprehends in the most perfect manner all things, hidden or manifested. But He is far greater than to be encompassed by the knowledge of His creatures. Allah the Supreme is the Creator of everything, for He has a free hand in the disposal of all affairs. He is the most Merciful, Whose unbounded mercy encompasses everything. He is far removed from injustice and tyranny. Allah's justice ensures order in the universe, which has no defect. There is no one to share His domain, nor does He take aid or support from His creatures. He is the God of the worlds. Yet, He is nearer to man than man's jugular vein. Whenever a believer in need or distress calls on Him, He responds. He is above the Seven Heavens mounting His throne is the manner which suits His grandure.
Allah has revealed His final Scripture, al-Qur'an to the last of His Messengers, Muhammad, peace be on him, to convey the Message of Islam to mankind. He is the Exalted Allah; Glory be to Him.
Taken from Islam In Brief