故事发生在南北战争前美国南方一个叫圣彼得堡的小镇上。汤姆·索亚生性顽皮，厌恶教会学校里枯燥无味的生活。他和野孩子哈克一道搞了很多恶作剧，甚至离家出走，结伴逃到荒岛上，幻想着能过上传说中的海盗和绿林好汉的冒险生活。一个夜晚，他约哈克到坟场玩耍，目睹乔埃杀人案，经过激烈的思想头斗争，最终挺身而出作证，揭露了乔埃的罪恶，成为孩子们钦佩的小英雄。乔埃企图杀害汤姆，结果反而困死在山洞里。汤姆和哈克发现了一大堆海盗埋藏的金币，两人因此都成了富翁。

　　主人公汤姆·索亚天真活泼、敢于探险、追求自由，不堪忍受束缚个性、枯燥乏味的生活，幻想干一番英雄事业。小说的时代在南北战争前，写的虽是圣彼得堡小镇，但该镇某种程度上可以说是当时美国社会的缩影。小说通过主人公的冒险经历，对美国虚伪庸俗的社会习俗、伪善的宗教仪式和刻板陈腐的学校教育进行了讽刺和批判，以欢快的笔调描写了少年儿童自由活泼的心灵。

Sparkling with mischief, jumping with youthful adventure, Mark Twain's Tom Sawyer is one of the most splendid re-creations of childhood in all of literature. It is a lighthearted romp, full of humor and warmth. It shares with its sequel, Huckleberry Finn, not only a set of unforgettable characters--Tom, Huck, Aunt Polly and others--but a profound understanding of humanity as well. Through such hilarious scenes as the famous fence-whitewashing incident, Twain gives a portrait--perceptive yet tender--of a humanity rendered foolish by his own aspirations and obsessions. Written as much for adults as for young boys and girls, Tom Sawyer is the work of a master storyteller performing in his shirt sleeves, using his best talents to everyone's delight.