The Chinese language has no tense but has aspects. It relies on aspectual particles to express how an action or state relates to the flow of time. Among all Chinese aspectual particles, le (了) is the most frequently used and is notoriously elusive for non-native speakers to grasp. Chinese Aspectual Particle le: A Comprehensive Guide is entirely devoted to le. It presents a systematic analysis of le and includes detailed illustrations of its usage. Breaking le down into le1 and le2, this book illustrates how le1 forms the perfective aspect: when it is obligatory, incompatible, or optional, and when le can be interchangeable with guo (?) and zhe (?). It shows how le2 denotes a change of state, performs as a modal particle, and is used in discourse. By comparing Chinese grammar with that of English whenever relevant, the book makes the usage of le more assessible to English speakers. It also contains a plethora of illustrative sentences, a wide range of vocabulary, and abundant cultural information.