In this paper, the concept of the conical focus is revealed, and the design of a solar cooker is explained. The cooker was practically tested for grilling both white and red meat in a record time. A method for obtaining real boiling of water (100degreesC) using a solar heater is described. The cooker was also tested for oil frying and for cooking beans. (C) 2002 Elsevier Science Ltd. All rights reserved.