Stamp Collection ID Help Needed - Pics Included - 1800's

So here's the scenario: My uncle came across this stamp album many years ago and gave it to me a few weeks ago so I could see if any of it was worth trying to sell. I know NOTHING about stamps and deal mostly in sports cards. The album is labeled "Imperial Stamp album' and dated 1899 inside. It has pages for multiple countries. I scanned the two US pages. Inside the album the original owner has numerous envelopes that contain stamps from various countries. I scanned some of the more interesting looking stamps (with historical people I could recognize). The book itself contains stamps (mostly from the same time period) from countries to include Cuba, Austria, Hungary, Belgium, Denmark, Finland, France, Germany, Prussia, Great Britian, Italy, Greece and Mexico. I'm looking to find out if this is worth invesing any time on or if these are just worth a few dollars. Any insight would be greatly appreciated. Also, if you know of another site that would be best to post this please let me know. Thanks!