Women may wear buttons but men may not. Men can use belts but not lotions. A certain ritual shower and shave are required, after which, men may not touch a woman, hunt, or use perfume.
And, please, 30 photographs and six copies of the participant's birth certificate are required for participation.
This was not the kind of knowledge that Abdellah Hammoudi was seeking when he decided to make a pilgrimage, or hajj, to Mecca in 1999. He was actually hoping for revelations of a much grander scope.
He did have some of those, but they arrived attended by a host of other phenomena, including major and minor disappointments, tears, joy, inspiration, dust, chronic fatigue, and - at almost every turn - a sea of jostling crowds.
All of this has been recorded in Hammoudi's A Season in Mecca: Narrative of a Pilgrimage (translated from the French by Pascale Ghazaleh), winner of a 2005 Lettre Ulysses award for reportage.
Hammoudi, who was born in Morocco and describes himself as a "secular Muslim" is a professor of anthropology at Princeton University. He decided to undertake this trip with the goal of writing a book about his observations.
Hammoudi's relationship with the faith of his childhood could best be described as uncomfortable. He still unequivocally views Islam as his "home," yet he no longer considers himself a believer. He is also troubled by questions about the "integrity" of treating the hajj as a secular experience.
"I am not a believer like the others," he writes. "I am approaching the hajj as I would a ritual from another religion. I am not contemptuous of religions; I believe that under certain conditions they allow for the expression of major existential dilemmas and encourage reconciliation on a grand scale."
But despite his disclaimer, Hammoudi cannot approach Islam as he would any other religion. Like it or not, he finds there not only nostalgia for his past self but also nagging questions about his own identity as an Arab who lives among the elite of the West, a man ill at ease on a "magnificent, chilly campus."
In reporting on his hajj. Hammoudi does sometimes achieve a measure of detachment - and even an occasional flash of sly humor. (The fast-food restaurants in Medina, he decides, edify the faithful by offering them "an unadulterated version of hell.")
But more often he wears his rather emotional heart on his sleeve. The things he does not like about the hajj seem to pain him deeply.
He is troubled by the narrowness of some of the ritual imperatives. He wonders about the segregation of the sexes. He is distressed by those among the faithful who push, shove, or bribe themselves into position. He also hates the frenzied shopping many pilgrims indulge in when not busy at prayer.
And he is very saddened by the degree to which the pilgrims seem divided by nationality rather than united by faith.
These observations offer readers an intimate, insider's account of the minutiae of a hajj, particularly intriguing for those of us who will never be able to come any closer.
Equally engaging are the moments when the anthropologist disappears and Hammoudi surrenders to feelings he can't explain, such as the surge of ineffable joy he feels at the Prophet Mohammed's tomb and the tears that fill his eyes at the first sight of the Kaaba, or Great Mosque.
Eventually, however, the academic in Hammoudi regains the upper hand and the book returns to the kind of intellectual wrestling the trip was intended to inspire.
Yet, in the end, for all the elegance of Hammoudi's reasoning, the task he sets for himself may be impossible, for who has ever been able to make sense of belief without resorting to faith?
• Marjorie Kehe is the Monitor's book editor.