Muthuswami Dikshitar (Mudduswamy Dikshitar): muttusvāmi dīkṣitar, 24 March 1775 – 21 October 1835), mononymously Dikshitar, was a South Indian poet, singer and veena player, and a legendary composer of Indian classical music, who is considered one of the musical trinity of Carnatic music. Muthuswami Dikshitar was born on 24 March 1775 in Tiruvarur near Thanjavur, in what is now the state of Tamil Nadu in India, to a family that is traditionally traced back to Virinichipuram in the northern boundaries of the state. His compositions, of which around 500 are commonly known, are noted for their elaborate and poetic descriptions of Hindu gods and temples and for capturing the essence of the raga forms through the vainika (veena) style that emphasises gamakas. They are typically in a slower speed (chowka kala). He is also known by his signature name of Guruguha which is also his mudra (and can be found in each of his songs). His compositions are widely sung and played in classical concerts of Carnatic music.

Muthuswami Dikshitar was born on 24 March, 1775, in Tiruvarur near Thanjavur in what is now the state of Tamil Nadu in India. He was the eldest son of the composer, Ramaswami Dikshitar who instructed in a number of subjects including the vedas, poetry, music, and astrology. Muthuswami had two brothers, Chinnaswami (Cinnasvāmi) and Balaswami (Bālāsvāmi),[b] and a sister, Balāmba.Muthuswami's father, Ramaswami Dikshitar, born circa 1735, from an Auttara Vadama family in Virinchipuram, had moved South due to the politically troubled environment around Kanchipuram and Virinchipuram at that time. Ramaswamy Dikshithar trained in the veena under Venkata Vaidyanatha Dikshitar, who belonged to the lineage of Govinda Dikshitar and Venkatamakhin and this is evident in Muthuswami's works which follow the Venkatamakhin raga system.

The musical trinity consists of Dikshitar, Tyagaraja (1767–1847), and Syama Sastri (1762–1827). However, unlike the Telugu compositions of the others, his compositions are predominantly in Sanskrit. He also composed some of his Kritis in Manipravalam (a combination of the Sanskrit and Tamil languages).

There are two schools of thought regarding the pronunciation of his name. The name is popularly pronounced as 'Muthuswamy Dikshitar'. Muthuswami is an extremely common Tamil name (Muthu translates to pearl in Tamil, cognate to Muktha/Moti in Sanskrit and Hindi) and is derived from Selvamuthukumaraswamy, a deity of the famed Vaideeswaran temple in Myladuthurai. However, T K Govinda Rao explains in Compositions of Mudduswamy Dikshitar that "the word Muddayya is an epithet of Kumaraswami or Guha. Further, in the most authentic original Telugu publication of Sangita Sampradaya Pradarshini (1904) Sri Subbarama Dikshitar transliterates his name as Muddu, for e.g, in the Bhajare-re Kalyani Krithi, "Muddu Kumara Janani" appears to refer to his mother.

Muthuswami Dikshitar attained mastery over the veena, and the influence of veena playing is evident in his compositions, particularly the gamakas. In his kriti Balagopala, he introduces himself as a vainika ga¯yaka, "a player of the veena". He experimented with the violin, and among his disciples, Vadivelu of the Thanjavur Quartet, and his brother Balaswami Dikshitar pioneered the use of violin in Carnatic music, now an integral part of most Carnatic ensembles.

On his return to Tiruvarur, he composed on every deity in the Tiruvarur temple complex including Tyagaraja (an amsham of Lord Shiva), the presiding deity, Nilotpalambal, his consort, and the Goddess Kamalambal an independent deity of high tantric significance in the same temple complex. This is when he composed the famous Kamalamba Navavarna kritis, filled with exemplary sahityas on the deities of the Sri Chakra which proved to be the showcase of his compositions. These navavaranams were in all the eight declensions of the Sanskrit language and are sung as a highlight of Guruguha Jayanti celebrated every year. He continued to display his prowess by composing the Navagraha Kritis in praise of the nine planets. The sahitya of the songs reflect a profound knowledge of the Mantra and Jyotisha sastras. The Nilotpalamba Kritis is another classic set of compositions which revived dying ragas like Narayanagaula, Purvagaula, and Chayagaula.

Muthuswami Dikshitar died on 21 October 1835 at Ettayapuram. He had no children. A samadhi was erected at Ettayapuram in his memory and attracts musicians and admirers of his art.

His total compositions are about 450 to 500, most of which are very widely sung by musicians today in Carnatic music concerts. Most of his compositions are in Sanskrit and in the Krithi form, i.e., poetry set to music. Muthuswami Dikshitar travelled to many holy shrines throughout his life, and composed krithis on the deities and temples he visited. Dikshitar is considered to have composed on the widest range of deities for any composer.[citation needed]

Each of his compositions is unique and brilliantly crafted. The compositions are known for the depth and soulfulness of the melody — his visions of some of the ragas are still the final word on their structure. His Sanskrit lyrics are in praise of the temple deity, but Muthuswami introduces the Advaita thought seamlessly into his songs, resolving the inherent relationship between Advaita philosophy and polytheistic worship. His songs also contain much information about the history of the temple, and its background, thus preserving many customs followed in these old shrines. Another noticeable feature in his compositions are the proficient rhyming of lines in the lyrics.

Muthuswami also undertook the project of composing in all the 72 Melakartha ragas, (in his Asampurna Mela scheme) thereby providing a musical example for many rare and lost ragas. Also, he was the pioneer in composing samashti charanam krithis (songs in which the main stanza or pallavi is followed by only one stanza, unlike the conventional two). Dikshitar was a master of tala and is the only composer to have kritis in all the seven basic talas of the Carnatic scheme. Dikshitar shows his skill in Sanskrit by composing in all the eight declensions.

For richness of raga bhava, sublimity of their philosophic contents and for the grandeur of the sahitya, the songs of Dikshitar stand unsurpassed.

Muthuswami Dikshitar composed many kritis in groups. Vatapi Ganapatim is regarded his best-known work.