Two copies are mandatory; one for the bookshelf, one for the car. The car copy will need replacing on at least a semi-annual basis. Essential for use at the nursery and very helpful as a field guide as well. The layout is well nigh ideal: photographs of each plant and all the essential information (size, light, water, color, feature, maintenance, wildlife, etc.) concise and auhtoritative in easy -to-follow table format. Whatever other issues they might have, Aggies do know plants. ( )