How to finish a book with 1000 pages?

Question

Books

Good afternoon,
please advise the methods of reading books, I want to read a book that has 1000 pages, the material is quite clear, but the following problems arise;
while I finish reading the page, I forget the previous one and can no longer retell it, respectively, there can be no question of mastering the material, and that I can apply knowledge in the future.
also, after reading 3-5 pages, I start jumping on other modules of the book, interest disappears and I start thinking about something else.
I tried to take notes on important points in the book, but the summary turns out to be very voluminous, since 80% of the material is important.
How to read and understand the material?

Answer 1

It depends on what kind of material it contains. If it's something that could be of practical use. Let's say programming, English, etc. Then it will be an undoubted blessing, together with reading, to put it into practice. Or problem solving.
If this is all theory ... Well, then, as I see it, only notes, cards with questions, for use in my free time. Something like this.

Answer 2

If you forget, you cannot master it, then you are not interested in what is written. Another option is that you do not put into practice what you read (for example, simply reading Horstmann's two-volume book will be of little use).
If it's technical literature, read/apply, move on. If something different but interesting, try to find another book. If necessary, but NOT interesting, just read .. something will remain ..