Island of Time is book number 28 in the Choose Your Own Adventure series. It was written by R.A. Montgomery.
A spur-of-the-moment trip to Providence Island turns into a voyage back in time. Do you turn back your boat when a dangerous storm starts brewing, or try to make it to harbor? Do you follow a mysterious ethereal voice you hear in the forest? What if you get stuck in a weird time loop? And what is your parents' accountant doing in the family lake house?