When left without any external obligations even for a couple of days I seem to wake up and go to sleep later and later each day. My rhythm doesn't settle on any fixed 24-hour period. Is something similar to this discussed in the book?

I have the same issue. I progressively sleep and wake later and later until I wake up around 1pm. I then force myself to reset my cycle and go to sleep before 2am.

I work from home and I have a lot of flexibility since I live in a different timezone from my clients so I make that work but it is frustrating for my wife. Workouts don't really seem to help much, melatonin seems to improve things slightly.

I wish I could just reset it and go to sleep earlier like that. I'll either just lay in bed wide awake or fall asleep for an hour or two and then not be able to sleep again for the next several hours.

Sometimes my clock gets so out of phase that I'll fall a sleep at around 10AM and sleep until 19PM or so. It's pretty tough to go back to regular schedule after that, heh.

Oh I make it sound easy to reset in my message but it's actually more akin to jetlag... I'm usually pretty much down for the count for 1-2 days

Have you tried strictly abstaining from LCD / artificial light usage 4-5 hours before bedtime? Might easier trying this on vacation somewhere rural.

We know that blue light is a strong cue to your brain to keep delaying the clock -- perhaps your brain is unusually sensitive to it.

Not the person you asked, but my experience was the same before I had any LCD's or smartphones. I did have artificial lighting of incandescent kind and CRT monitor.

CRT would have the same effect

I use flux which does restrict somewhat the amount of blue light I have.

I do tend to work late at night because of timezone differences between me and my clients.

One thing you could try is safety goggles that block UV:

https://www.amazon.com/gp/product/B000USRG90

My experience with flux was that the screen still gave off enough blue light that it didn't make much of a difference for me.

Good idea, I'll try that

Delayed Sleep Phase Syndrome

Seems increasingly common with our modern lifestyle.

http://my.clevelandclinic.org/health/articles/delayed-sleep-...

The poster probably is: I'm much the same way.

Low functioning on little sleep, but a good night or two and I'm up at 1am.

Right now, I simply sleep when I'm tired and waking when I please most days. I generally sleep from about 4am to noon, approximately. Additionally, sleeping later in the day produces a better sleep. I sporadically sleep through alarms and loud noises.

It does make the normal 8-5 world more difficult to deal with.