History
Outside of South Asia, pure instrumental sub-continental classical music is more popular than vocal music, possibly because the lyrics in the latter are not comprehensible.
A number of musical instruments are associated with Hindustani classical music. The veena, a string instrument, was traditionally regarded as the most important, but few play it today and it has largely been superseded by its cousins the sitar and the sarod. Other plucked/struck string instruments include the surbahar, sursringar, santoor and various versions of the slide guitar. Among bowed instruments, the sarangi, esraj (or dilruba) and violin are popular. The bansuri (bamboo flute), shehnai and harmonium are important wind instruments. In the percussion ensemble, the tabla and the pakhavaj are the most popular. Various other instruments (including the banjo and the piano) have also been used in varying degrees.
Some representative performers (these lists are by no means comprehensive nor are intended to be):

Veena: Dabir Khann, Birendra Kishore Roy Chowdhury, Zia Mohiuddin Dagar, Bahauddin Dagar, Asad Ali Khan, Suvir Misra, Jeff Lewis
Vichitra Veena: Dr. Lalmani Misra, Pt. Gopal Krishna, Dr. Gopal Shankar Misra,Mrs.Radhika Budhkar.
Sitar: Imdad Khan, Enayet Khan, Wahid Khan, Mushtaq Ali Khan Ravi Shankar, Vilayat Khan, Nikhil Banerjee,Manilal Nag, Purnendu Shekhar Sengupta(Kanu Babu), Rais Khan, Abdul Halim Jaffer Khan, Imrat Khan, Shahid Parvez, Indranil Bhattacharya, Santosh Banerjee, Kalyani Roy, Budhaditya Mukherjee, Sanjoy Bandopadhyay, Kartik Seshadri,Shri ShriRam umdekar Purbayan Chatterjee
Sarod: Allauddin Khan, Brij Narayan, Hafiz Ali Khan, Radhika Mohan Moitra, Timir Baran, Ali Akbar Khan, Jatin Bhattacharya, Buddhadev Das Gupta, Vasant Rai, Sharan Rani, Dhyanesh Khan, Aashish Khan, Ustad Amjad Ali Khan,Mukesh Sharma
Surbahar: Imdad Khan, Wahid Khan, Enayet Khan, Annapurna Devi, Imrat Khan
Shehnai: Bismillah Khan, Ali Ahmed Khan
Bansuri: Pannalal Ghosh, Hariprasad Chaurasia, Raghunath Seth, Bari Siddiqui
Santoor: Shivkumar Sharma,Tarun Bhattachrya, Bhajan Sopori, Omprakash Chaurasiya
Sarangi: Ram Narayan, Bundu Khan, Ustad Sultan Khan, Abdul Latif Khan
Esraj: Ashesh Bandopadhyay, Ranadhir Roy
Violin: V. G. Jog, Gajananrao Joshi, N. Rajam, Allaudin Khan, L. Shankar, L. Subramaniam, Kala Ramnath, Sisir Kana Dhar Choudhury
Harmonium: Pt. Gyan Prakash Gosh,Pt. Manohar Chimote,Ustad Zamir Ahmed Khan,Ustad Bhure Khan
Tabla: Gyan Prokash Ghosh,Shankar Ghosh,Ahmed Jan Thirakwa, Anindo Chaterjee, Chatur Lal, Shamta Prasad, Kanthe Maharaj, Alla Rakha, Arup Chattopadhyay, Anokhelal Misra, Keramatullah Khan, Kishen Maharaj, Zakir Hussain, Aban E. Mistry, Yogmaya Shukla,Shubhankar Banerjee, Subrata Bhattacharya, Debashis Choudhury.
Guitar, slide (modified): Brij Bhushan Kabra, Vishwa Mohan Bhatt, Debashish Bhattacharya Instrumental music
Despite the fact that instrumental music is better known outside India, Hindustani classical music is primarily vocal-centric, insofar as the musical forms were designed primarily for vocal performance, and many instruments were designed and evaluated as to how well they emulate the human voice. Some of the best known vocalists who sing in the Dhrupad style are the members of the Dagar lineage, including Us. Wasifuddin Dagar, Us. Fariduddin Dagar, and Us. Sayeeduddin Dagar. Among the khayal singers, the best known today are Pt. Balkrishnabuwa Ichalkaranjikar, Pt. Shankarrao Vishnu Pandit, Pt. Eknath V. Pandit, Pt.Ramkrishnabuwa Vaze, Pt.Shivram Vaze, Pt. Vishnu Paluskar,Pt.B R Deodhar, Pt. Srikrishna Narayan Ratanjankar,Pt. Shankarrao Vyas, Jagjit Singh, Pt. D.V.Paluskar, Pt. Vinayak Rao Patwardhan, Pt. Narayan Rao Vyas, Pt. Anant Manohar Joshi, Pt. Yashwant Mirashi buwa, Pt. Gajanan Anant Joshi, Pt. Shankar Rao Vyas, Pt. Omkarnath Thakur,Pt. Eknath Sarolkar, Pt. Rajabhaiyya Poonchhwale, Balasaheb Poonchhwale, Pt. Pandurang Rao Umdekar, Pt. Balabhau Kundal Guru, Ustad Amir Khan, Pt Bhimsen Joshi, Mallikarjun Mansur, Pt. Kumar Gandharva, Basavaraj Rajguru, Ustad Bade Ghulam Ali Khan, Kishori Amonkar, Prabha Atre, pandit madhav gudi,Gangubai Hangal, Rajan and Sajan Mishra, Pandit Jasraj, Parveen Sultana, Malini Rajurkar,Pt. Ulhas Kashalkar,Vidushi Sumitra Guha [1], Ustad Badal Khan, Viswadev Chatterjee, Prasun Bannerjee,Yogiraj Manohar Harkare,Pt.Gangadhar Bhagwat, Meera Bannerjee, Gyan Prokash Ghosh, Chinmoy Lahiri, Begum Akhtar, Gauhar Jan, Malka Jaan, Siddheswari Devi,Hifzul kabeer

Vocal music
The major vocal forms-cum-styles associated with Hindustani classical music are dhrupad, khayal, and thumri. Other forms include the dhamar, tarana, trivat, chaiti, kajari, tappa, tapkhayal, ashtapadi, ghazal and bhajan. Of these, some forms fall within the crossover to folk or semi-classical ('light' classical) music, as they often do not adhere to the rigorous rules and regulations of 'pure' classical music.

Types of compositions
Dhrupad is the Hindu sacred style of singing, traditionally performed by male singers. It is performed with a tanpura and a pakhawaj as instrumental accompaniments. The lyrics, which were in Sanskrit centuries ago, are presently sung in Brajbhasha, a medieval form of Hindi that was spoken in Mathura. The Rudra Veena, an ancient string instrument, is used in instrumental music in the style of Dhrupad.
Dhrupad music is primarily devotional in theme and content. It contains recitals in praise of particular deities. Dhrupad compositions begin with a relatively long and acyclic Alap, where the syllables of the mantra "Om Anant tam Taran Tarini Twam Hari Om Narayan, Anant Hari Om Narayan" is recited. The alap gradually unfolds into a more rhythmic Jod and Jhala sections. This is followed by a rendition of Bandish, with the pakhawaj as an accompaniment. The greatest of Indian musicians, Tansen sung in the Dhrupad style. A lighter form of Dhrupad, called Dhamar, is sung primarily during the festival of Holi.
Dhrupad was the main form of northern Indian classical music until two centuries ago, but has since then given way to the somewhat less austere, khyal, a more free-form style of singing. Since losing its main patrons among the royalty in Indian princely states, Dhrupad ran the risk of becoming extinct in the first half of the twentieth century. Fortunately, the efforts by a few proponents from the Dagar family have led to its revival and eventual popularization in India and in the West.

Dhrupad
A form of vocal music, khayal is almost entirely improvised and very emotional in nature. A khyal consists of around 4-8 lines of lyrics set to a tune. The singer then uses these few lines as the basis for improvisation. Though its origins are shrouded in mystery, the 15th century rule of Hussain Shah Sharqi and was popular by the 18th century rule of Mohammed Shah. The best-known composer of the period was Sadarang, a pen name for Niamat KhanAdarang,Manrang and kadar bakhsha,Nisar Hussain Khan Gwalior wale..
Later performers include Ustad Alladiya Khan, Abdul Karim Khan, Pt.Dattatreya Vishnu Paluskar, Faiyaz Khan, Pt.Vinayak Rao Patwardhan, Pt. Shankar Rao Vyas, Pt.Narain Rao Vyas, Ut.Nazakat Ali And Ut. Salamat Ali Khan, Pt.Eknath Sarolkar, Pt.Kashinath Pant Marathe, Bade Ghulam Ali Khan, Kesarbai Kerkar, Mogubai Kurdikar, Krishnarao Shankar Pandit, Amir Khan, Pt. Gajananrao Joashi, Pt. Ram Marathe, Pt. Ratnakar Pai, Kumar Gandharva, Jitendra Abhisheki, and Mallikarjun Mansur.
Some of the present day vocalists are Bhimsen Joshi, Gangubai Hangal, Pt. Yeshwantbua Joshi, Girija Devi, Kishori Amonkar, Pandit Jasraj, Satyasheel Deshpande, Iqbal Ahmad Khan, Dr. Rajshekhar Mansur, Pt Ulhas Kashalkar, Pt. Arun Bhaduri, Malini Rajurkar, Prabakar Karekar, Rashid Khan, Aslam Khan, Sanjeev Abhyankar, Shruti Sadolikar, Ashwini Bhide, Ajay Pohankar, Chandrashekar Swami, Pt. Venkatesh Kumar, Mashkoor Ali Khan Pt. Parameshwar Hegde, Indrani Choudhury, Pt. Ganapathi Bhat.

Khayal
Another vocal form, Tarana are songs that are used to convey a mood of elation and are usually performed towards the end of a concert. They consist of a few lines of rhythmic sounds or bols set to a tune. The singer uses these few lines as a basis for very fast improvisation. It can be compared to the Tillana of Carnatic music.

Tarana
Thumri is a semiclassical vocal form said to have begun with the court of Nawab Wajid Ali Shah, 1847-1856. There are three types of thumri: Punjabi, Lucknavi and poorab ang thumri. The lyrics are typically in a proto-Hindi language called Braj bhasha and are usually romantic.

Thumri
Ghazal is an originally Persian form of poetry. In the Indian sub-continent, Ghazal became the most common form of poetry in the Urdu language and was popularized by classical poets like Mir Taqi Mir, Ghalib, Zauq and Sauda amongst the North Indian literary elite. Vocal music set to this mode of poetry is popular with multiple variations across Iran, Afghanistan, Central Asia, Turkey, India and Pakistan. Ghazal exists in multiple variations, including folk and pop forms but its greatest exponents sing it in a semi-classical style..

Principles of Hindustani music

Indian classical music
Carnatic music
Raga
Tala
Gharana
Sitar