Each book contradicts itself because they are written according to different theories. 12 hours of sleep is fine, but it doesn't have to all be at night. Night and naptime sleep should equal to about 12 hours for the day.
When I studied infant and toddler development in college, we looked at the different theories and decided that the one that worked best, is what works for the child.
For my children, I find that putting them to bed a bit later gets them to sleep longer. They go to bed around 7:30pm to 8:30pm (sometimes later) and sleep anywhere from 8am to 9am.
They also only take one nap a day. Well, my 3 year old refuses to nap at all, but I will put him in his room for "quiet" time to play or hopefully fall asleep if not.
My just turned 1 year old takes one nap a day, right after lunch usually around 1. Sometimes, he will need a before lunch nap, but it is very rare.
Also, early waking is a phase. When a child has discovered something new or hit a new milestone, like pulling up, walking, talking... it is typical for them to lose sleep over excitement/anxiety/frustration to practice the new skill. Once they have it mastered, the sleep cycle usually returns to normal.