Day0020 SB 1.2.3 - 4

Let me offer my respectful obeisances unto him [Śuka], the spiritual master of all sages, the son of Vyāsadeva, who, out of his great compassion for those gross materialists who struggle to cross over the darkest regions of material existence, spoke this most confidential supplement to the cream of Vedic knowledge, after having personally assimilated it by experience.
Before reciting this Śrīmad-Bhāgavatam, which is the very means of conquest, one should offer respectful obeisances unto the Personality of Godhead, Nārāyaṇa, unto Nara-nārāyaṇa Ṛṣi, the supermost human being, unto mother Sarasvatī, the goddess of learning, and unto Śrīla Vyāsadeva, the author.



Śrīmad-Bhāgavatam is the natural supplementary commentary on the Vedānta-sūtras.
The Vedānta-sūtras, or the Brahma-sūtras, were compiled by Vyāsadeva with a view to presenting just the cream of Vedic knowledge. Śrīmad-Bhāgavatam is the natural commentary on this cream.
to show his boundless mercy upon bewildered materialistic men who want to cross completely over nescience, Sukadevji recited for the first time this confidential knowledge.
No materialistic creature — be he the great Brahmā or an insignificant ant — can be happy.
Everyone tries to make a permanent plan for happiness, but everyone is baffled by the laws of material nature.
Therefore the materialistic world is called the darkest region of God’s creation.
unhappy materialists can get out of it simply by desiring to get out
compared to the camel who relishes thorny twigs because he likes the taste of the twigs mixed with blood. He does not realize that it is his own blood and that his tongue is being cut by the thorns. 
Out of hundreds of thousands of karmīs, only a few may feel tired of material engagement and desire to get out of the labyrinth. Such intelligent persons are called jñānīs.
Bhāgavatam is the original commentary on the Brahma-sūtras.
 Śrīla Vyāsadeva also instructed the Bhāgavatam to his own son, Śrīla Śukadeva Gosvāmī, who was already at the liberated stage of transcendence.
Śrīla Śukadeva realized it personally and then explained it.
By the mercy of Śrīla Śukadeva, the Bhāgavata-vedānta-sūtra is available for all those sincere souls who want to get out of material existence. 

Śrīpāda Śaṅkarācārya intentionally did not touch it because he knew that the natural commentary would be difficult for him to surpass.
From this introductory śloka, the beginning student should know that Śrīmad-Bhāgavatam is the only transcendental literature meant for those who are paramahaṁsas and completely freed from the material disease called malice.
The envious Māyāvādī cannot have access to the Bhāgavatam, but those who are really anxious to get out of this material existence may take shelter of this Bhāgavatam because it is uttered by the liberated Śrīla Śukadeva Gosvāmī. 
It is the transcendental torchlight by which one can see perfectly the transcendental Absolute Truth realized as Brahman, Paramātmā and Bhagavān.

All the Vedic literatures and the Purāṇas are meant for conquering the darkest region of material existence
If one at all wants to conquer this perpetual struggle for existence, he must reestablish his eternal relation with God. 
And one who wants to adopt such remedial measures must take shelter of literatures such as the Vedas and the Purāṇas
the Purāṇas are supplementary explanations of the Vedas intended for different types of men.
There are men who are conducted by the mode of goodness, others who are under the mode of passion and others who are under the mode of ignorance. The Purāṇas are so divided that any class of men can take advantage of them and gradually regain their lost position and get out of the hard struggle for existence. 
Śrīmad-Bhāgavatam is the spotless Purāṇa, and it is especially meant for them who desire to get out of the material entanglement permanently.