Quit! Close the book if it bores you unless you need to finish it for a job or a class lesson. Put books away that you do not enjoy. Good books are like good food; the more enjoyable they are, the faster you need to finish them. Have an ingrained tendency to finish any book you start even if it slumbers midway? It is common to dedicate time to finishing a book you invested in or lifted from a shelf. If you do not enjoy your read it can be agonizing. If you are a literary glutton and want to read as much as you can, boring books can backslide and slow down your productivity of reading. You may start about four novels and pack them away for every one that you pick up and are enticed to get to the end. Do not throw the first four books down in rage, quietly say ‘ this one is not for me’ and put it aside. No rage required.
Give it a fair chance. Best is, get to page 50.
If there are no fireworks and you are no longer impressed, entertained, or remolded in the direction you need to be in, shelve it. Ask yourself is it worth it If yes, keep reading, If not look for another book to read. You can worm yourself back into that shelf of ‘books apart’ in time if you desire in six or sixty years time.