I am installing 3 1/4" x 3/4" prefinished oak throughout a fairly large completely open area 35" x 30' (great room - dining - kitchen) with a 4' wide hallway beyond.
Visualize a rectangle ( I can almost see eveyones eyes start to glaze over) with the top & bot being the 30' walls & the left & right being the 35' walls with a hallway heading away from the middle of the left 35' wall
The oak will be running lengthwise parallel to the 30'-0" direction.(spanning left to right) & will continue on into the hallway.
Would it be better to start the 1st strip along the 30' exterior wall and the rows would the proceed to the opposite wall 35' across
OR
Split the area in half & start in the center ( in line with one of the hallway walls beyond) and the rows would proceed 17'+ each way to each opposing 30' walls. (with a splined joint)
It is a very cold dry winter & am concerned that the boards will expand with moist spring/summer air and that by starting in the center I will lessen any expansion effect.
Is it worth the extra effort to start in the middle? The oak has been acclimatizing for months (at least thats what I have told my wife)
Thanks in advance.

IMO, start off at one of the hallway walls so you only have one end row to deal with. Before nailing anything check the starting line to see if the hallway is square to the main room and how wide the last row boards will be. You may decide to rip a little off the 1st row in the hallway. Check your line at several points front and back.

Start off on of the hallway walls, ensuring it is parallel to the room walls as JerrY said.
The theory behind starting in the centre of large spaces is that, although the floor boards will expand or contract individually, the direction of travel of the floor system is generally in the direction the tongue faces. By starting in the centre, you will have equal movement (if any) in both directions.

Thanks Jerry & Dennis for the replies.
Just to clarify:
You are saying that starting from the center is the best way to go.... theoretically... but would it be unadvisable to start from one of the 30' walls?
I guess what I really want to ask: if you guys were installing in a rect 30" X 35' room (parallel to the 30' wall & ignoring the hallway) (in a cold dry winter in Calgary, Alberta) would you start from one of the walls or in the center?
Sorry for belaboring the point.

Just stating the way I would approach this morley. It does not have to be exact room center. If the hallway is close to the room center I prefer to make one long starting line, first seeing how it's going to hit everywhere before I start nailing. As Dennis said it is recommended to work both ways in a room of that size.