In the name of Allah, the most compassionate, the Merciful.
And pilgrimage to the House is incumbent upon men for the sake of Allah, (upon) every one who is able to undertake the journey to it; Holy Quran, (3:97)
The word Hajj means to intend, to win over someone by argument and frequently visit someone. As a religious term it refers to the act of worship: circumambulating the Kaaba (Tawaf, praying and performing the other prescribed deeds).
Hajj is the Pilgrimage to Makkah in Islam. Hajj is the fifth of the Five Pillars in Sunni Islam and one of the ten Branches of religion (Obligations of Islam or Furo-e-Deen) in Shia Islam, which takes place during the Islamic month of Dhu al-Hijjah. Entrance to Makkah itself is forbidden to non-Muslims and the entire city is considered a holy site to Islam.
Baitulla is another name for Kaaba, is a sacred house in the center of Masjid-e-Haram in Makkah and Baitulla means House of Allah. Hence Hajj-e-Baytullah, Hajj-e-Baitullah or Hajj-e-Baitulla means Pilgrimage to the House of Allah.
This is the Worship (Ibadat) that becomes obligatory once in a lifetime. Therefore, its conditions, its difficulties and its rewards are unique.
Those who are able to fulfill this obligation are indeed privileged. But this privilege can become a ban instead of a boon if it is misused. And it is easy to misuse it. Misuse takes the form of oblivion of the rules, carelessness in performance of the rites and ignorance of the importance of the rites of Hajj in the living of one's life.
Therefore, the more sincere effort the Haji (Person who performs the Hajj) puts in, the greater the reward, and this Guide is an aid to this sincere effort according to the fatwa of Ayatulla Al-Uzma Agha Seyyid Abul Qassim Al-Musawi Al-Khui (RA).