Bruso:It's amazing to me how learning a language (or learning anything significant) must be justified as "useful", when nobody asks that question when spending long weekends watching sporting events, or endless hours listening to pop music, or spending a day shopping for trivial items.

Amen Brother! Preach it! )

But seriously, I agree. It's basically a hobby. Hobbies have no need of being useful, just enjoyable, and as far as I'm concerned, Esperanto makes for an excellent hobby. It 1)Has a large community to discuss and share the hobby with 2)Has a useful component 3)Promotes personal development/growth (because you are learning) and 4) Opens you to a wider world. Doesn't matter if your hobby is ham radio, bicycling, woodworking, programming, knitting, gardening, or Esperanto.

Although I respect the OPs point of view, I don't really understand or agree with the statement that its not useful as opposed to a natural language. I speak reasonably proficient Russian, and aside from talking to the relatives, it doesn't carry a lot of water for me. Opportunity to speak it: Gotta go to Russia (not the easiest place for a foreign traveler to get around). Opportunity to speak Esperanto: Gotta go...somewhere (generally rather closer than Russia though). Literature in Russian: Huge literary tradition in Russian...which is BUTT KICKING HARD to plow through without a ton of effort attaining fluency. Literature in Esperanto: Much more accessible to a non-expert, but also much more limited in scope. Still, there's always the thought that you might run across a real gem thats not available in other languages, or translations of works that are ONLY available in foreign languages you don't speak. And most languages don't have things like Esperanto houses where you can stay while traveling and Pasporta Servo (although there is now Couchsurfing). Looking for an excuse to go on a trip? There's always a congress going on somewhere (France 2015 here I come!), and while you can learn, for example Japanese, and get more in depth into the local culture doing so, you're limited to just Japan. There's always going to be Esperanto speakers in most any country you can connect with, and having visited over 40 countries, I can say that making those connections is not always easy in English.

jdawdy, try reading "Vojaĝo al Kazohinio". It is a thick book but an easy read. Koloscay (spelling?) used a classic vocabulary (though some terms are old fashioned - they would be in English or any other language as well - he wrote it about 80-90 years ago). There is an English translation which they claim is translated from Hungarian, but he actually wrote the novel in Esperanto.
Esperanto is a badge of my internationality. I wear it, quietly, not "fanfarone") and it means more to me than any other language (my first two languages are German and English - I was born in the US but my very first, "grandmother" language is German - my grandma raised me).
Esperanto is my inner way of being a mondano before being an usonano, my commitment to my world view.
Esperanto forces me to try to formulate things on a world scale - there is no temptation to use regionalism (that's like Calle Ocho*) or nationalisms (put your John Hancock on something)or even "Anglicisms" (the whole 9 yards). You are forced to seek an international mode of expression in within the language. That alone is an exercise in clear thinking.
Look up "homaranismo" (in Esperanto) on Wikipedia. The Esperanto entry is much longer and more detailed than the English-language one but I think you will find my thoughts there. Zamenhof really got to hearts with that document.

* Here in Southeast Florida Calle Ocho [ka-ye otchoe) is the biggest block party and a real Miami-style, international bash - so it stands for "a great party time".

robbkvasnak:jdawdy, try reading "Vojaĝo al Kazohinio". It is a thick book but an easy read.

A quick Google search did not immediately turn up an online or e-version. It the book available in PDF or Mobi or only available in hard copy?

Vojaĝo at flibusta: fb2 and pdf.
You can find many other esperanto books there. But you must register for download not in Russian.

Thanks a lot, sergejm. I didn't know that ressource. To find some Esperanto literature there someones has to write search term 'Esperanto' with cyrillic letters 'Эсперанто'.

Could it be that without registration someones also can not search whole stock of books there?

Without registration, you will see author without books (or with Russian translation only).
To find all books in Esperanto: flibusta.net/new/eo
(There are 9 pages of books in the list)
But textbooks and dictionaries, bilingual book etc. are marked by other language.