In what order should I read the various Buddhist scriptures? Well, first of all, I don't consider myself a strict Buddhist, but I want to study Buddhism -- both Theravada and Mahayana -- for educational and spiritual purposes. I am very excited with scientific studies of Buddhist meditation, and I'm sure that the Buddhist teachings have a lot of interesting and helpful things to offer...

I have one small book on the philosophy of Buddhism, there are 19 sutras with the commentaries on each sutra. But the book is a bit wordy due to its specificity, and heavily influenced by the author... The texts (I suppose) are translated well, with the meticulous description for every specific term (like, "Tathagata", or "dukkha" etc.)...

But when I decided instead to start to read the Pali Canon directly, not this compilation, and found out that Pali Canon is huge, even Sutta Pitaka alone seems to be way bigger than the Bible...
And it seems that the sutras are not composed chronologically or from simple to difficult, so I suppose there is no need to read the book in strict order...

So, how do you suggest reading the sutras? In strict order? Randomly? Or, from the 'popular' sutras to the 'unpopular' ones?

Do I even need to read the whole Sutta Pitaka? Do I need to read Abhidhamma Pitaka and if yes, in which order?

And what of Mahayana's important texts?

I'll appreciate all of your recommendations (and don't be afraid to correct my grammar, because English is not my native language).
I have read MN, then SN, then AN - so that's another way to sequence it. Then you can read Questions of King Milinda.  Then Tattvasiddhi Śāstra by Harivarman also known as Satyasiddhi Śāstra, Then Vasubandhu's Abhidharma-kosa. Then the Rice Seedling sutra. Then try Vimalakirti sutra. Then Diamond sutra. Then Heart sutra. Then Nagarjuna's Mulamadhyamikakarika.