Read only as fast as you can understand what you're reading comfortably. Reading is not a speed contest, remember you want to benefit from the material - especially when it is work related.
Underline and mark special segments of text
I underline shorter phrases, but for whole paragraphs I put a vertical line in the margin next to the paragraph indicating it's length.
Use markings like NB (for very important) or * for special attention and so on. Use whatever makes sense to you - but be consistent.
Fold a corner of the page you want to refer to
Once you've finished dreading the book, don't put it aside
What you should do is
spend an extra hour and MindMap it.
Finally, MindMaps of certain valuable books can serve as an excellent topic of conversation. If you find that a friend, or colleague has read a particular book, you may ask them to swap MindMaps. It's a great way of establishing similarities with people and for gaining a different angle on a favourite book.