The multiple layer historical city is a living and functioning city, as anyother - it is inhabited by people, different activities take place in it, and itmust answer to various needs, according to its general definition as a city.But it has a distinctive dimension - the dimension of depth-, in more thanone sense: contents and values derived from its history, and physical multi-layered depth, where its hidden roots are contained. The character of thiscity is derived from that depth. Its physical layout is loaded with memories of urban structures buried beneath it, and their marks are revealed, invarious ways, above the ground.The aim of this research is to analyze and establish the methods of learningand principles for the design and development of a multiple layer historicalcity, according to its special nature. The city of Acco was chosen as a casestudy.The importance of learning and establishing guidelines for approaching thefuture development of the multiple layer historical city, increases with theunderstanding that such cities will probably not be created in the future,and therefore its number is limited. So, such cities are to be conserved as atestimony of urban-historical processes which have passed from the world.This thesis basic assumption is, that further stages in the design and plan-ning of the multiple layer historical city should be based on an ideology ofconnecting to the past.For that purpose a deep theoretical survey and discussion of four basic is-sues is done; the multiple layer historical city and its particular nature; thehistory of the city and its role in the city systems; the city and its compo-nents, and finally, the issue of conservation.Based on that discussion, conclusions for learning and designing the multiplelayer historical city are formulated. The special learning stages requiredfor such a city are described. Design principles, both in the ideological andphysical levels are, as well, established.Finally, the learning methods and the design principles for the multiplelayer historical city suggested in this work, are demonstrated in the designof the city of Acco. Guidelines for the design of Acco are presented, startingwith the whole town, through the old city and ending with a detailed descrip-tion of part of it.These design guidelines demonstrate how historical and multiple layer com-ponents can and should be combined in the urban system, as integral part ofits planning, and by this to contribute to an enrichment of its contents.