The Lost Journal of Indiana Jones purports to be the journal that Indy was given by his father before the start of their journeys in the television series. The first page in the book contains his father's admonition to record what "Junior" sees and learns. On the page after, we find that Indy lost his journal to the Russians, and is annotated by them, presumably to learn what they can about the archaeologist.
The journal is filled with Indy's observations and notes from throughout his life, based on the incidents and adventures in the television series, and the films (with one exception, "Old Indy", the man who recounts the stories of his life in the television series, is not represented, presumably because by that point he had stopped having adventures. So if you have seen the movies and the books, you will know most of what the "Lost Journal" contains.
The book was enjoyable, but many things broke my willing suspension of disbelief. For one thing, many early pictures in the book have been doctored (probably with photoshop) to include the very recognizable faces of Harrison Ford as a small boy and Sean Connery as a young man. Other pictures are of the male actor who played young Henry Jones Junior in the TV series. This presents problems when they are nothing alike! (Young Harrison Ford is dark-haired, the actor who played young Indy is dark blonde, and their faces don't look in the least bit like each other to me.z) Also, the younger Sean Connery doesn't look anything like the actor who played Dr. Henry Jones, Senior in the television series, either.
The other thing that leapt out at me is that presumably, Indiana Jones had only one journal all his life? With all his adventures and the things he did? That beggars the imagination. Even if he kept the journal only infrequently, it would seem that a man with such an adventure-filled life would have filled up more than a single journal.
On further reflection, the journal is too nice looking. Remember what Indiana Jones goes through in his adventures. I'd expect it to be beat up, with water-smeared pages and many, many more stains, spots and smudges than are presented in the pages.
My biggest gripe is that it gives us no new insights into the character of Indiana Jones, just information we could have gotten from watching the TV show or movies, which basically makes it just one more useless piece of fan crud. Now, I must say that journal tie-ins to movies aren't all bad. I have a leather-covered journal from the "League of Extraordinary Gentlemen" movie as part of my collection of fan crud. The difference? It's an actual blank journal you can write in, which at least makes it useful.
The book was entertaining, and it was a good idea, but the lack of logic and continuity kept throwing me out of the pleasant fantasy that I was supposed to be having, that I was actually reading the supposed Journal kept by Indiana Jones. As such, it was a less than successful book for me. And at the price you are expected to pay for this experience, $25 US, I wouldn't waste my money on this at all.