Digital chess books

My best recommendation is chessable.com. They have free books on every subject matter to let you experience their trademark MoveTrainer technology. As for the selection, they have chess books that have been converted to their MoveTrainer format, and they have an army of chess masters churning out materials every month.
There's also ChessKing.com which I think was the first to use the interactive chess book on PCs then online.
I started a forum post about it here if you would care to read it and the contributions of fellow chess.com members:
https://www.chess.com/forum/view/general/forward-chess-chess-studio-e-chess-books-chess-king-chessable

Try using a real board & pieces while following the e-book . . .
But i suggest to get real book using the real board & pieces . . .

Check it out...(as chessroboto reccommended earlier).....
online chess books/courses.....(many are free)...

Check out Forward Chess (www.forwardchess.com)
They specialize in chess ebooks, combining the book and the board. They seem to have the largest catalog by far, with hundreds of latest titles from multiple publishers.
How about something on chessable? They have both free and paid stuff. From free I really would recommend the Magnus stuff like https://www.chessable.com/the-magnus-touch-free-strategy-lesson/course/40115 from the paid I personally enjoyed the this books https://www.chessable.com/sharp-middle-games-a-practical-guide-to-chess-calculation/course/17599/ about the calculations