Retiredbum notes: I talked about Hanyu Pinyin several times in my previous writings.  Please check them in the "lingustics" category of my blog.  Attached below is another brief article about Pinyin that I found at BackChina.com, which will give you a concise history on the development of the system.  BTW, both English and its Chinese translation are beautifully written.  It is worth your while to read it.

Anyone, who is planning to learn Chinese in China or overseas, should be very grateful for the current pinyin system that is in use.

　　但凡要在中國或海外學中文的，都得感謝現行在用的拼音體系。

　　Romanisation of the Chinese language began back in the 1600s through the Jesuit missionaries but the works were solely for a western audience.

　　漢語羅馬化要追溯到17世紀的耶穌傳教士，但其著作僅僅面對西方受眾。

　　It is common to come across the Wade-Giles pinyin system in history text books or hearing people talk about China who haven』t learned modern pinyin.

　　經常在歷史教科書看見威妥瑪式拼音法，未學過現代拼音者談論中國時也會論及。

　　Compared to the logic of the modern system of pinyin there are clear flaws. Mao Zedong was written as Mao Tse-tung. The 『tung』 phonetic for 東 is not accurate standard pronunciation and so the Wade-Giles system would always be lacking.

　　較之現代拼音體系，威妥瑪式拼音法有明顯缺陷。Mao Zedong（毛澤東）寫出來是Mao Tse-tung，而用tung表示「東」的發音並非準確的標準發音。因而威妥瑪式拼音法總是有所欠缺。

　　Modern hanyu pinyin was a project pushed by the Communist Party in 1950. Led by Zhou Youguang, the team』s aim was to create an all-encompassing phonetic system without the inaccuracies of previous systems.

　　現代漢語拼音是共產黨1950年推進的項目。 由周有光引領，團隊旨在創造全面的拼音體系，剔除之前體系不準確的標音。

This seemingly exhaustive list provides the all the phonetic possibilities in the language. The tones are signified by markers, known as diacritics, above the key syllable of the final.

　　這一體系幾乎窮盡了中文裡所有可能的語音。音調由標記標出來，即人們所知的變音符號，標在韻母的關鍵音節上。

　　Pinyin can be important for Chinese adults as well as foreigners and schoolchildren as it reminds people of the standard pronunciation opposed to their local dialect.

　　拼音對於外國人和在校學生重要，對於中國成年人一樣重要，因為拼音提醒人們注意有別於其當地方言的標準的發音。

　　It』s possible, and realistic, that in the near future school children all over the world will be learning Chinese as part of their syllabus.

　　不久的將來，很有可能世界各地的在校學生會學習中文，漢語成為其課程大綱的一部分。