Yes, chess books are time consuming, frustrating and at times BORING.
If it's an opening book (or a GM's best games book) the best method to learn is to cover up the moves with a sheet of paper and spend a considerable amount of time on each and every move. When you feel happy with the move you made, slide down the paper to uncover the next move and you'll be amazed at how much you missed in the position.
It will take you a good 4-5 hours to fully digest a single game this way, but for good reason! You're making significant progress.
I have 4 books, close to memorising the two but the other two are game after game that I want to memorise before the next purchase.
... I have juts bought my first serius chess book, and I see that is extremely time-consuming, not a lot of diagrams, and full of coordinates, just to read 10 pages, with a chess board in front of you takes a lot of time, but the book have 160 pages! so I do not know how much time it can take me! and I do not have much time, it is a bit discouraging, If I did that, I would not have the time to play in moths. ...
I think that, to a large extent the solution, as many have already indicated, is to go for some sort of electronic book. I would just like to add that, for many opening books, I think that they are written to be a combination of instruction manual and reference. The idea seems to be that the reader skip much of the reference material and consult it only after playing a game that raises a question addressed by the reference material.
In a 2006 GM John Nunn book, in connection with opening study, it is stated that, if a "book contains illustrative games, it is worth playing these over first", and the reader was also advised, "To begin with, only study the main lines - that will cope with 90% of your games, and you can easily fill in the unusual lines later."
In one of his books about an opening, GM Nigel Davies wrote (2005), "The way I suggest you study this book is to play through the main games once, relatively quickly, and then start playing the variation in actual games. Playing an opening in real games is of vital importance - without this kind of live practice it is impossible to get a 'feel' for the kind of game it leads to. There is time enough later for involvement with the details, after playing your games it is good to look up the line."
"... I feel that the main reasons to buy an opening book are to give a good overview of the opening, and to explain general plans and ideas. ..." - GM John Nunn (2006)