19MB!!! That's pretty big for an Ebook. Blockchain is something that you learn practically. Of course a book would help but I think you should learn it from your effort and work and experience, with just a little help from a book to understand the thoughts and meanings and mechanism.
the book that Jet Cash shared with us "thank you for that" isn't just free, but is going thru:
- Blockchain 101
- Decentralization
- Cryptography and Technical Foundations
- Bitcoin
- Alternative Coins
- Smart Contracts
- Ethereum 101
- Ethereum Development
- Hyperledger
- Alternative Blockchains
- Blockchain-Outside of Currencies
- Scalability and Other Challenges
- Current Landscape and What's Next
you should make an effort in reading this Book, you won't regret it.