Latin script is the most popular in the world, used by 38,5% of all human beings in 51% land. It is the prime script for sciences. Many signs in non-Latin scripts are transliterated into Latin as well.
In Latin script a letter usually represents a single sound (consonant or vowel). This makes the script suitable to write most languages of the world as every language is composed of sounds.
However as Latin has been adopted for many different languages new ways had to be created to represent additional sounds, leading to letters with diacritics (“Ž”, “Ą”), or digraphs (two letters for a single sound: “Sh”, “Kh”).
Each letter has two forms: capital and non-capital. Capital letters are used in special circumstances (first letter of sentence, name, etc.). All other letters are non-capital.
The script evolved in the Greek cities of southern Italy. It came to its true glory after it has been adopted by the Roman Empire for its official Latin language. At that time only block capital letters were used.
Between 4th century BC and 2nd century AD Romans conquered southern Europe, western Middle East and Northern Africa. Latin language and script was used for inscriptions all over the Roman Empire, especially in the west.
Roman Empire withered and collapsed in the 5th century AD but by this time Western Christian church had established itself in Rome, adopting Latin language and script as means to disseminate the Holy Bible. And the Bible spread. Central and Northern European nations became Christian by the 13th century and Latin was the language learned to communicate with foreigners. It was only natural that when a need arose to write their native languages Latin script was also adapted.
Europe was however suffering “Dark Ages”, its culture (including Latin script) thrown out of Africa by advancing Arabs. This definitely ended by 15th century when Europeans discovered America. European empires then partitioned the world by conquering colony after colony using their superior weapons and science. Subjected nations had to adopt Christianity, and with it the Latin script, adapted for local languages by countless missionaries. Latin script replaced Arabic as the world’s most popular. It became the prime script in whole America, Australia and Sub-Saharan Africa.
By 19th century Europeans were so confident in the superiority of Latin script (or that of a single global script) that some empires made replacing other scripts an official colonial policy (Malay, Vietnamese, Hausa, Somali languages). Even entire independent countries (Turkey) switched to the script for the purpose of Westernization.
In mid-20th century most colonies acquired independence but Latin script has already been well entrenched and no former colony abandoned it. Most of the international achievements that required a single script (e.g. programming) are thus now done in Latin script, or at least Latin script is the major way. Non-Latin-script languages thus adopted official transliteration standards to help international communication.