The Mystery of the Silver Spider is in many ways the quintessential Three Investigators book in my mind, mainly because this title stands out the most from my childhood memories. It really is a good, exciting story, full of political intrigue, international espionage, a dastardly conspiracy, very real danger, a mad flight to safety, and other thrills along the way. After a chance meeting with the young prince of Varania, the boys find themselves invited to the prince's coronation in his home country. They are ostensibly contracted by the U.S. government to serve as secret junior agents--while the feds know some type of trouble is brewing in the small yet important European nation, they have been unable to ferret out the information they need themselves and thus turn to our intrepid young heroes for help. Once in Varania, the prince confides in them the fact that the invaluable silver spider, the symbol of Prince Paul, the most important leader in their history, and the symbol of the very nation, has been stolen and replaced with a fake; without the true silver spider, the prince will be disgraced and his coronation will be postponed--perhaps permanently. Much to the boys' surprise, Bob finds the precious spider stashed among his handkerchiefs. Realizing that the evil plotters mean to blame them--the young prince's friends--for the theft, Jupe, Pete, and Bob are forced to make a run for safety; fortunately, they are aided by some Varanians loyal to the young prince. Poor Bob bangs his head during the escape and cannot remember where he stashed the real spider. As events build to a climax, the boys race to free themselves from capture and somehow alert the Varanian people to the prince's danger. With Bob still suffering partial amnesia, it is up to Jupiter to find the silver spider and thus save not only the prince but the entire nation of Varania.
This one is action-packed from front to back and may well be the best book in the series. If you have not yet been introduced to the Three Investigators and are wondering which book to try reading first, I would recommend this book. You might as well buy the other available titles, though, because you are surely going to want to keep reading these adventures. For the life of me, I can't figure out why there has never been a Three Investigators movie--this story in particular would be terrific on the big screen.