According to the official rules of pinyin, should 道德经 be transcribed with or without spaces between the individual syllables?
Most of foreigners use emphasized text &quot;Tao Te Ching&quot;. Of course, it's not in Mandarin Chinese Pinyin, but in old Chinese Pinyin. It is very common, such as Peking and Sun Yat-sen. And, how to write it in Mandarin Chinese Pinyin?
Rules:
There should be a space between two words what mean different.
《现代汉语词典》 Xiàndài Hànyǔ Cídiǎn
《毛主席语录》 Mao Zhuxi Yulu
《市民准则》 SHIMIN ZHUNZE
Here's the exact rule:

书报名、标题名可以全部大写，也可以每个词开头的字母大写，有时为了美观，可以省略声调符号。如：
儿童文学 ERTONG WENXUE
《现代汉语小词典》，复旦大学出版社，P1011

To solve this problem, we need to know is &quot;道&quot; and &quot;德&quot; in one word, or have different meaning. I searched for it, and got to know:
&quot;道&quot; is &quot;天地万物的演化运行机制(The evolutionary operating mechanism of the universe)&quot;.
&quot;德&quot; is &quot;人的素质或者事物品质(Quality of people or things)&quot;.
Also, there are two parts in &quot;Tao Te Ching&quot;, 《道经》 and 《德经》. So, it should be &quot;Dao De Jing&quot;.
Why not &quot;Daode Jing&quot;?
In modern Chinese, &quot;道德&quot; is one word, means &quot;人们共同生活及其行为的准则和规范(The rules and norms of people living together and their behavior)&quot;. It's different to &quot;道德&quot; in《道德经》.
Actually, you can also translate it yourself. For example, you can translate it into &quot;Theory of Everything and Code of Conduct in all the Time in Life&quot;(my bad translation). But I still think &quot;Tao Te Ching&quot; is the best choice because it is common. When people see this title, they knows which book it is in a few seconds.