Best Way to Joint panels where they meet at a cross?

[Sputnik0003]

OK, badly described in the title and probably a stupid question, but:

I want to make some shelves that effectively look like boxes (i.e. a grid pattern).

It seems obvious how to join the horizontal shelf to one of the verticals, but how do I fit the next vertical on top of that invisibly?

All I can think of so far is dowelling.

Any smart solutions?

Thanks

 

[big-all]

dowels biscuits rebates will all work

you can half screw though
fully assemble the side and shelves leaving the back off


all the first divider can be screwed top and bottom
the second one up needs to start with a dowel this will require the shelve to be lifted about 25mm easily done on mdf

cut all your spacers at the same time to be identical make the top row 5mm bigger
put the bigger spacers to one side
lay the sides back to back
using an off cut as a marker draw a line across one side and mark the other cut where the bottom is place your off cut on the line draw a line above the off cut
whithout moving the off cut place a divider on top off it draw a line across place off cut on divider repeat until you reach the top dont use a spacer for the top it goes at the top

mark the both sides off all shelves at the same time using the off cut to give you your 2 lines that all screws and dowels will be inbetween

 

[foxhole]

You could assemble using halving joints and glue, no dowels no screws required.Just lots of cuts.
This is a variation on the theme.
http://www.instructables.com/id/Hungarian-Shelves/

 

[ladylola]

Exactly what do you mean by invisibly?
Personally I'd go for stopped housings i.e. a groove that dosen't reach the front edge of the shelf, simple enough with a router and not much more difficult by hand. Actually pretty much as foxy says.