After we downsized to a much smaller house, I had difficulty storing my books. I had books all over my desk, and they were always in my way, so I'd set them aside on the floor, and there they'd stay until they were scattered everywhere. Not only that, but most of them were stored in a bin in the garage, which wasn't very convenient. I didn't want to put more books in the garage, because then I couldn't get them easily (not to mention possibility of moisture damage), but I didn't want them taking up the whole desk either! So finally I decided to build myself a bookshelf. I had a 1x10 board left over from another project, so I based my design around that, using various scraps and pieces of wood I had on hand in the garage. Now all my books are together in one place, and there's still space for a few more! And if that space fills up, well then, I can build another! :-D

As always, if anything is unclear, please let me know in the comments and I'll do my best to clarify!

Step 1: What You Need:

Materials:

1x10 board as long as you want your shelf to be (mine was 4 feet, I wouldn't really recommend going longer)
2x2 about 6-8 inches shorter than board (I used a deck/porch baluster like this)
A 1x4, about 16 inches long, or two 8 inch pieces
A 2x3, about 18-20 inches long, or two 9 or 10 inch pieces (I had a lot of these chunks of 2x3 left from a closet framing project, if you don't have a 2x3, you could probably do it with 2x2)
A 3/4 or 1 inch dowel, about 25 inches long, or four 6 inch pieces (I used an old broken tool handle, it had been on a shovel I think (Edit: I think maybe it was actually a broom handle. It looks more like a broom handle. But whatever it was a handle to has been gone for years, so I can't say for sure))
A 1x2, about 20 inches long, or two 10 inch pieces (I had a couple options on this one, but finally went with a broken bench slat, left over from when we repaired the bench)
Wood screws, 1 1/2 inch or so
Four or five 2 inch screws for mounting
Wood glue (I used Gorilla brand)
Paint or other finish, if desired

Tools:

Circular saw, if you need to shorten your 1x10
Miter saw or miter box, for cutting everything else
Drill, and bits slightly smaller in diameter than the screws. Also a countersink bit, if desired
Screwdriver, preferable electric
Drill press, and Forstner bit the same diameter as your dowel (If you've got a really steady hand, you might manage with a normal drill, but I wouldn't try it!)
Router and router table, with desired edge bit (I used a simple bevel edge)(optional, but looks nicer)
Sandpaper
Extendable clamps (C-clamps aren't big enough to clamp the bookends)
Measuring tape
Pencil
Paintbrush (if painting or finishing)
Masking tape (if painting)
Level (for mounting)

Also:

A friend to help hold it up while you mount it on the wall!

Step 2: Cutting the Wood for Shelf

First, make sure the 1x10 board is the length you want. If it's too long, mark the desired length with a pencil (careful now! Measure thrice, cut once!), and cut off excess with a circular saw.

Then, cut the 2x2 to 6-8 inches shorter than the board, with the miter saw / miter box. In my case, the board was 48 inches, so the 2x2 was 40 inches. I originally wanted it to be 42 inches, but the piece I had was too short for that. The only difference is how much the shelf overhangs the supports; and it doesn't matter much whether that is 3 inches or 4.

Then cut the angled support pieces from the 2x3. The wide edge should be about 9 or 10 inches (mine was about 9 1/2). Cut the end at a 45° degree angle with a miter saw or miter box, as shown. It is very important that the cuts be perpendicular, not parallel! It should be shaped like a trapezoid, not a parallelogram. I cut mine from two separate pieces, because they were scraps leftover from a closet framing project, but if you cut them from a single piece, cut them so one is oriented the opposite direction of the other, as in the pictures, to minimize wasted wood.

Then it's time for the 1x4. I actually didn't have any extra pieces of 1x4, so I used a table saw to cut the extra chunk of 1x10 into two pieces the shape and size of a 1x4. Same result either way :-). Anyway, I held the 1x4 chunk and the angle piece up to the board, in the position they'd be in the finished shelf, and marked the 1x4 in the place that looked most aesthetically pleasing. That ended up being 7 1/2 inches. Then I cut it straight across (don't accidentally cut it at 45°!) with the miter saw.

Step 3: Routing the Edges (optional, But Looks Better)

I wanted the shelf to have a little more of a refined look, and less of a made-of-scrap-lumber look, so I beveled the edges with a routing table. Do a test piece to make sure the bit is positioned properly, then bevel the long edges of the angle supports (not the end), one edge of the 2x2, both long edges and one short edge of the 1x4 pieces, and both short sides and one long one of the 1x10 board. You may need to make multiple passes through the router. It didn't end up perfectly straight for me, but it looks fine. Any obvious irregularities can be smoothed out with a sanding block.

On the large board, the beveling will be on the bottom edge. So you'll have to decide which side is top and which is bottom at this point. I recommend, if the wood is bowed (usually is), to orient it so that it bulges up in the center, not down. That way, the weight of the books over time will tend to decrease the curve rather than increase it.

Now, ideally I wouldn't be wearing a bulky winter coat while doing this, but since it was January, in Colorado, in an unheated garage, it might have been more dangerous to not wear it, as I'd be shivering so hard I'd end up hurting myself on one of those tools or another!

Step 4: Drilling the Holes and Cutting Wood for Bookend

Take your 1x2 (or bench slat, or whatever), and cut it to the width of the 1x10 board. You'll want it as close the the exact length as possible. I then sanded the ends, so they would match the rounded, weathered edges of the old bench slat.

Cut the dowel (or tool handle, or whatever) into four 6 inch pieces. Make them as close the exactly the same length as possible.

Measure 1 inch from each end of the 1x10, and make a line. Make a line lengthwise down the center of each 1x2 piece. Then decide where you want the dowel holes to be. I made mine with the center of the dowel 2 1/8 inches from the edge of the board. Carefully measure and mark this point. Then measure and mark the same distance from each end of each 1x2 piece. Check to make sure each pair of marks has the same distance between them! This is important, because one end of the dowel will be in the board, and one end in the "railing", and if the holes in each piece aren't the same distance from each other, the bookend won't fit together properly.

Once you have made sure your markings are where they need to be, get ready to drill. I very strongly recommend using a drill press for this; I can't imagine trying to manage without one! Use a test scrap to get the hole to the desired depth in the wood (1/4 inch or so), and make sure the dowel fits in the hole. Then carefully center the drill bit on the markings in the wood. For the main board, I had to prop it up, as shown. Drill the two holes in each end of the board, and in each "railing" piece. Verify that the holes in the smaller pieces line up with the holes in the board.

Step 5: Assembling the Shelf Supports

Center the 2x2 on the un-beveled edge (back) of the main board, on the bottom of the board. Position it a "1x4-thickness" away from the edge. In other words, there will be just enough space for the 1x4 to fit behind it, and not hang off the edge. Clamp the 2x2 in place and turn the board over. Drill pilot holes, slightly smaller than the diameter of the screws, at intervals along this edge. Make sure you are drilling into both pieces of wood. Use a countersink bit in each hole, if desired, to keep screws from protruding on the top. Then screw the pieces together through the holes. Then turn the board over again. Clamp the 1x4 at the end of the 2x2, with the un-beveled edge against the board, and the un-beveled surface facing the edge of the board. This will be the part that goes against the wall; the beveled side will be the side you see. Of course, if you skipped beveling the edges, than just position it so that whichever part looks best to you will be visible. Drill a pilot hole into the back of the 1x4, into the 2x2, and screw in place. Repeat at other end.

Then place one end of the angled support against the 1x4, and one against the main board. Unfortunately nobody was around to take my picture when I was doing that, so I don't have any photos of it :-(. Basically I just put the support where it was centered side-to-side on the 1x4, and held it in place with all my might while I drilled the pilot hole through the back and screwed it in place. Then I turned the shelf over, and drilled from the top and screwed the pieces in place. One support fit together fine the first time, the other I had to drill, screw, unscrew, drill, and re-screw a couple times to get it right. One thing to note is that if your main board is warped (usually is), there will be a gap between the main board and the support, where one edge of the end of the support touches the board, and the other doesn't. You could try to fill it with putty or something, I just decided not to worry about it.

Step 6: Assembling the Bookends

Now it's time to assemble the little "railing" bookends, so the books don't fall to their death! XD

Put a bit of wood glue into each hole in one 1x2, and insert one end of a dowel into each glued hole. Then put glue in each hole in one end of the shelf, and insert the other ends of the dowels. Then clamp it in place, tweaking its position as needed for it to be straight and square. Repeat at other end of the shelf, and set aside for the time recommended in the glue manufacturer's instructions.

Step 7: Painting/finishing (if Desired)

Now it's time for the finishing touches! I originally meant to paint the whole thing except the top surface of the shelf (I'm scared of books sticking to the paint), but then I liked the bare wood so much I decided to only paint the bookend part. But there's nothing to keep you from painting however much you like :-D.

My favorite way to get paint for small projects is to find clearance or mistinted interior latex at a hardware store such as The Home Depot. As you can see, this can cost only $3. If I had known I was only going to paint the bookends, I would have gotten a smaller can! But oh, well, guess I've got some for something else if I need it!

You can see how I used a scrap of the dowel to trace a semi-circle (slightly more than semi, actually) on pieces of masking tape. I then used scissors to cut along the arc, and thus was able to mask neatly against the dowel.

For re-coating and drying times, follow paint manufacturer's instructions.

If you would rather use stain and varnish or another finish, follow manufacturer's instructions.

Step 8: Mount It on the Wall!

Now let's mount this for all to admire!

Drill two pilot holes into the inside edge of each 1x4 support piece, where the screws are in the picture. Then locate a stud. This will be heavy with all those books on it, so you'll definitely want it screwed into a stud! Line up the holes in one support with the stud, and have someone help you hold it up while you screw a 2 inch screw into one of the holes. Then, with it still being held up, put a level on the top, and adjust the position of the shelf until it's level. Then screw into the other hole. Screw into the holes in the other support. Now, for added support, you can locate another stud within the length of the shelf. Drill a hole into the 2x2 in line with the stud, and put in another screw.

Note that the supports may not be completely parallel, and thus not sit flat on the wall at first. But this is generally rectified when they get screwed down, so don't panic! :-)

I happened to have a couple of hook racks from Dollar Tree, and found that they fit perfectly under the shelf! So now I can not only store books, but also hang odd objects on the wall! XD

I've included the before and after pics, as usual the lighting isn't great, but you can see that one has the desk taken over by books (not to mention the ones on the floor and in the garage), and the other has a nice clear space for all my crafting, writing, coloring, etc!