Planning concept and its contemporary significance shown in the "General Theory of Urbanization" written by Ildefonso Cerda

西班牙土木工程师塞尔达（Ildefonso Cerda）于1867年撰写的《城市化通论》（General Theory of Urbanization）可以被认为是世界上最古老的综合性和独特的规划理论之一，因为他继续发表了他的理论概念，提出了一种新的学说，他称之为“城市化”。对其《通论》进行了包容性研究，结果如下：会议的主题是街道街区的逐步构成、道路网络分析以及有助于实现城市项目的财政和技术方法。每个主题都是在讨论围绕1859年提出的巴塞罗那扩展计划所写的特定理论时指定的。

"General Theory of Urbanization" written by the Spanish civil engineer Ildefonso Cerda in 1867 can be placed as one of the oldest comprehensive and unique planning theories in the world in that he continued to publish his theoretical concept for a new doctrine, which he called "urbanization". The inclusive study on his General Theory was done, and the results can be described as follows; the main themes were the gradual composition of street-block, the road network analysis and financial and technical methods that would help contribute to the realization of urban projects. Each theme had been specified in discussing the particular theory written around the Extension Plan for Barcelona proposed in 1859.