Mind Map and review. If the information is important enough get more of your intelligences working to connect it to memory by mind mapping.
What people don't realise, reading uses at best 2 of our intelligences Analytical and Literary. However memory works better if you use more of the other senses as well. So Draw, get your hands involved and even consider part of your purpose could be to explain it to others and be prepared to explain it.
Having comprehension immediately after reading is one thing calling it up in future is a case of use it or lose it. Most books are forgotten after 6 days because that's the span of the memory based on needed information.
The best way to make it accessible in the long term is to start using it straight away, first step for that is mind map and use more of your intelligences.
Alex