How It All Goes Down
First, the structural deets: Gandhi's autobiography is divided into an intro, five parts with chapters, and a closing. Most chapters are short and cover a brief episode or two in his life. His account is pretty much in chronological order. The intro outlines his quest for truth, and the closing sums it up, so they show the big-picture message.
Part One gives us Gandhi's birth (October 2, 1869), childhood, teens, and time in England. He's influenced as a kid by his religiously tolerant political official father and devout mother. At age 13 (!), he's married to Kasturbai in a child marriage, meaning she's a teenager, too, and their parents are the ones who decide they should get married.
After a few years, she becomes preggo with the first of Gandhi's four children. Once Gandhi's father dies, a family friend suggests Gandhi go to England to study law to keep the family a high status one. However, his caste tells him it's against their religion for him to travel abroad.
Meanwhile, his mother is worried he'll lose his way in the foreign culture and start drinking alcohol, eating meat (his family is vegetarian), and sleeping with women other than his wife, who's to stay at home in India while her husband has his big adventure. Gandhi tells his caste he's definitely going to England, and they can go ahead and kick him out…which they do.
As for his mother's concerns, Gandhi takes serious vows not to touch alcohol, meat, or other women. With that, he's off to England. After being called to the bar (i.e., after officially becoming a lawyer), he returns to India.
Part Two tells us all about his time in South Africa, where he goes to work with a law firm. He gets kicked off a train due to "color prejudice" (which is what he calls racism), and he decides to fight back—non-violently, of course. He continues studying religion and founds the Natal Indian Congress. He heads back to India for a while, where he meets his mentor Gokhale and others, but is soon recalled to South Africa to continue "public work," which is his term for what we today might call activism.
In Part Three, Gandhi develops his spiritual practice of self-restraint by taking the brahmacharya vow of celibacy—by now, he's had his four sons, all with Kasturbai—and develops his political power by leading an Indian ambulance corps in the Boer War. He returns to India, where he attends the Indian National Congress and stays with Gokhale, his mentor. He also practices law there. When his second son becomes very ill, Gandhi refuses the doctor's advice to give him meat broth, which goes to show how seriously our author takes his religious ideals. Gandhi is full steam ahead by this point for sure.
Part Four has Gandhi fighting the Asiatic Department in the Transvaal, giving legal advice to Johannesburg Indians in land acquisition cases, organizing an Indian Volunteer Corps for the Great War, and more. He tells us about his religious studies, his experiments in diet (fruits and nuts only: dang), and his thoughts on the brahmacharya vow. He's glad to be celibate, saying that life with sex is "insipid and animal-like." He feels the self-restraint of celibacy is a purifying practice that makes him a better seeker of truth.
Part Five shows Gandhi at the height of his political power. He founds the Satyagraha Ashram in Ahmedabad, secures help for peasants in Champaran, fights the Rowlatt legislation, suspends Satyagraha after people become violent, edits newspapers, and gets a non-cooperation resolution passed by the Nagpur Congress. And that's just some of what he does politically.
There's also his decision to drink goat's milk when a doctor recommends it for a terrible illness. Gandhi had seen all milk as an animal product, like vegans do today, but decided he needed strength for his public work and that his vow to his mother not to touch milk only encompassed buffalo and cow milk. Gandhi writes that even if drinking goat's milk doesn't violate the letter of his vow, it violates the spirit, and he feels quite conflicted and pained over his choice.
And that's a wrap!