The book's blurb says "The most popular pirate story ever written in English" and they are not kidding about it. Practically every pirate tale written since then was influenced by this classic. I do not think I really need to mention the plot as it is widely known, but I will do it just in case.
A young boy named Jim Hawkins got his hands on a map showing the location of a buried pirate treasure - by a pure accident. A group of people is ready to go on a treasure hunt, but their plans are about to be destroyed by pirates who also want to get the treasure.
This is a classic adventure which also happened to have some very well written characters. First and foremost of such is Long John Silver. He is one of the most morally ambiguous characters from the genre. He was famous enough to have a chain of restaurants named after him, among other things. Another brilliant character which comes to mind is half-mad Ben Gunn (is he really?)
Strictly speaking this novel rates closer to 4 stars than 5, but I will raise the rating due to respect for the classic and its influence (as the most recent example: Captain Jack Sparrow would not exist without this novel).
This review is a copy/paste of my LeafMarks one: https://www.leafmarks.com/lm/#/users/10968/books/15328/review