Making the Thousand Year Notebook
works of  Carl C Pisaturo
This book uses Borden and Riley #234 paper, in the form of a 14" x 17" pad.  The pad has 40 sheets, enough to make a 160 page book. (a folded sheet has 4 surfaces). Procedure:

1) Pull of the sheets from the pad.  Back and forth "page turning" helps sheets release easier.

2) Fold sheets in half carefully on a smooth flat surface. I clamped down a metal parallel to act as a stop to help with alignment of the fold, and used a bone knife to make the crease.  Accurate folds take some practice, but will save time later.  Poorly done folds will require much sanding later.   You now have a stack of 8.5" x 14" folded sheets.

3) Using good paper cutter and a clamped down stop, cut off 3" of height from each
folded sheet.  You now have a stack of 8.5" x 11" folded sheets.

4) Set up a 45 degree clamp setup and mark the paper cutter to aid in consistently  clipping corners.  About a 1/4" triangle should be removed from each OUTER corner.  These corners will be fully rounded-over later, this clipping operation gets rid of most of the material.

5) Group the folded sheets into folios of 4 (4 folded sheets nested together is one "folio").  You now have 10 rough folios.

6) Flatten the fold ends of the folio by holding the folio on a thin ruler (ruler in the middle of the folio, folds pointing up) and running the bone knife along the folded edge. Invert, grip the folio closed and press the fold onto a table surface and rock.  By dialing back the sharpness of the folds, the paper sits better in the folios (less variation of edge protrusion).  You now have 10 ready-to-use folios.
The key feature of this book is that the folios are sewn onto the leather spine.  This is what gives the ability to open flat, as well as providing excellent strength.

The reason this approach is unusual is that it is more difficult and labor intensive to do. 

If efficiency mattered, you'd sew the book with one needle and a long piece of thread - going back and forth: into the folio, loop, outward, loop, inward...  But since the leather spine "blinds" you, it's impossible to sew from the outside inward - you could never get the positioning just right and hit the fold edge  That's why this method only sews from the inside outward.

This is labor intensive indeed... the needles need to be rethreaded EVERY stitch.

Each stitch or "loop" requies 2 needles on a single short length of thread.  In the drawing at left, 2 loops are sewn into a folio, tied off, and epoxy locked. (in the actual book, 3 loops are used).

The epoxy locks (yellow dots in the drawing) are small dabs of 5 minute epoxy at the points where the thread comes through the leather.  These lock the polyester thread loops to the leather snug and strong, preventing loosening of the folios with time and usage; The epoxy prevents micro-tearing of the leather at these high stress spots, and also serves as backup to the knots.

Each folio is done this way. For this book, that's 10 to 13 repetitions. It takes around 2 hours including the epoxy step which is done at the end.

That's the basic principle. In practice there are some complexities related to accurately sewing these multiple folios to a single piece of leather: the leather spine must be kept taught, the folios must be compressed and kept aligned, and the needles must be pushed through horizontally and at the correct left-right positions in the folios.

The sewing rig (photo montage below) solves these practical problems.
HEAD AND TAIL SEWING. (3 photos below)  Now that each folio is attached by 3 loops of thread, the book block is pretty stable.  But since the ends of the book block (the head and tail) take much of the stress of handling, they will be sewn also. 

First, linen fabric reinforcement strips are lightly PVA glue-tacked on to further stablize the ends of the leather spine. 

Fortunately, the geometry of the situation at the head and tail is easy to deal with, and the sewing goes quickly with a single length of thread sewn in a spiral pattern.

The ends of the thread are tucked and tied and lightly PVA glue coated so they can't unravel should thread breakage occur.  The book block now is quite rugged.
PLEASE NOTE REGARDING PHOTOS BELOW: the photos depict construction steps on 3 different notebooks.  Although the steps are similar in each case, the leather colors and some details differ.
SANDING.  The last step of making the book block is sanding.  The page edges of a hand made book will never be perfectly aligned, and this is not necessarily a problem, but I wanted to round-over the corners and improve the line-up somewhat to help make page flipping easier - thus the sanding.  There are giant machines to cut the perimeter of book blocks, and in mass production that's how it would be done, but for small runs, hand-sanding is doable.

Paper edges actually sand quite easily with 150 grit paper, but it takes lots of time to do so many of them neatly.

The first step is to clamp-down the book block as straight as possible and sand the perimeter en-masse.  Keep going until the corners look nicely rounded and the sides look even.  This is about a 10 minute very dusty job.

Next the book block is taken out of the clamp.  There are severe "burrs" (slanted build-ups of paper from the sanding process) , especially on the outermost pages, which must be removed.

The pages are lightly edge sanded using a block (photo left) one page at a time.  This gets rid of all burrs, fixes any corner rounding inaccuracies, and gives a very nice feel to the edges.  This process takes about 2 hours - and is the most boring and labor intensive part of the book process.

Compressed air helps clean the paper dust away, and the book block is done.  Ready for cover attachment.  
The covers are made of 1/8" bronze tinted polycarbonate - a strong and impact-proof plastic.  It is sanded to hide the scratching of normal use.    The covers are dadoed on the spine side to accomodate the thickness of the leather spine shield (photo right) which should sit flush in the finished product.

Attachment to leather requires pre-papering the dadoed zone with 3M 90 spray adhesive.  The subsequent epoxy bonds thus can load-spread over the papered zone, greatly reducing the possibility of peel failure.

A final sewing / epoxy operation completes the extremely robust joinery between the covers and the leather spine.